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Ajoure
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Ajoure is a style of jewellery design similar to filigree, which leaves open spaces in the worked metal. Unlike filigree, the holes are usually cut from the metal rather than being incorporated during the process of construction. It is usually used in the making of gold or silver jewellery.
Alloy (silver & gold jewellery alloy)
Alloy or alloys - in jewellery making, are created when two or more metals are combined to form a new type of metal with different characteristics.
The addition of specific components to an alloy makes it possible to alter the alloy’s mechanical properties (strength, hardness, elasticity, and resilience) and technical properties (flowability, casting shrinkage, malleability, weldability, and suitability for cutting), as well as the color of an alloy.
Silver and copper, among other metals, are added to gold alloys to alter the color from light yellow to reddish and to increase alloy strength, zinc and cadmium are added to significantly reduce the melting point and to increase flowability, and palladium and nickel are added to impart a light color, including white.
Silver Jewellery Alloy
1. Fine .999 Silver
It is marked .999 which indicates 99.9% purity. The 0.1% remainder consists of trace elements of insignificant quantity. Fine silver has a more vitreous luster than the bright polish of sterling but is less common in jewelry because is quite soft and will scratch, dent and change shape, items will not wear well over time.
2. Sterling .925 Silver
Sterling is the international silver jewellery standard in the most world markets. It is an alloy of 92.5% silver. The remaining 7.5% is usually copper though it is sometimes other metals such as nickel what is not recommenced because cause of allergic reactions in many people. Some countries regulate the amount of nickel that can be contained in piercing jewelry, now requiring it to be less than 0.05%
The most common quality stamps for Sterling Silver Jewellery are .925.
Most of today's silver jewellery is Rhodium-plated for increases shine, luster and durability. Additionally, it will make your jewelry more resistant to scratches, less prone to tarnishing and makes your jewelry hypoallergenic.
More about Rhodium-plating you can find in section: "R"
Gold Jewellery Alloy
Pure gold, 24kt, is very soft and not suitable for jewelry making.
For most uses of gold the pure metal is too soft on its own and is therefore hardened by the addition of alloying elements, copper, silver, nickel, palladium and zinc.
Carat of gold is expressed in parts of pure gold per 1000, as per the following examples:
,750 fineness, the measure for 18ct gold indicates 750 parts of gold per 1000 or 75% gold;
.375 fineness, the measure for 9ct gold indicates 375 parts of gold per 1000 or 37.5% gold.
White gold is an alloy of gold and at least one white metal (usually nickel, silver, or palladium).
Like yellow gold, the purity of white gold is given in karats.
Platinum Alloy
Platinum is one of the rarest of the precious metals. Naturally white, platinum will not fade or tarnish – keeping its natural white colour forever. Platinum is also a very strong metal. Its purity makes it hypo-allergenic and ideal for those with sensitive skin. Similar to gold, the purity of the metal is expressed in parts per 1000 and can be identified through its hallmark.
Platinum jewellery is marked with one of the following: Platinum, Pt, Pt950, Plat, Plat 950. The standard is 95% purity.
The addition of specific components to an alloy makes it possible to alter the alloy’s mechanical properties (strength, hardness, elasticity, and resilience) and technical properties (flowability, casting shrinkage, malleability, weldability, and suitability for cutting), as well as the color of an alloy.
Silver and copper, among other metals, are added to gold alloys to alter the color from light yellow to reddish and to increase alloy strength, zinc and cadmium are added to significantly reduce the melting point and to increase flowability, and palladium and nickel are added to impart a light color, including white.
Silver Jewellery Alloy
1. Fine .999 Silver
It is marked .999 which indicates 99.9% purity. The 0.1% remainder consists of trace elements of insignificant quantity. Fine silver has a more vitreous luster than the bright polish of sterling but is less common in jewelry because is quite soft and will scratch, dent and change shape, items will not wear well over time.
2. Sterling .925 Silver
Sterling is the international silver jewellery standard in the most world markets. It is an alloy of 92.5% silver. The remaining 7.5% is usually copper though it is sometimes other metals such as nickel what is not recommenced because cause of allergic reactions in many people. Some countries regulate the amount of nickel that can be contained in piercing jewelry, now requiring it to be less than 0.05%
The most common quality stamps for Sterling Silver Jewellery are .925.
Most of today's silver jewellery is Rhodium-plated for increases shine, luster and durability. Additionally, it will make your jewelry more resistant to scratches, less prone to tarnishing and makes your jewelry hypoallergenic.
More about Rhodium-plating you can find in section: "R"
Gold Jewellery Alloy
Pure gold, 24kt, is very soft and not suitable for jewelry making.
For most uses of gold the pure metal is too soft on its own and is therefore hardened by the addition of alloying elements, copper, silver, nickel, palladium and zinc.
Carat of gold is expressed in parts of pure gold per 1000, as per the following examples:
,750 fineness, the measure for 18ct gold indicates 750 parts of gold per 1000 or 75% gold;
.375 fineness, the measure for 9ct gold indicates 375 parts of gold per 1000 or 37.5% gold.
White gold is an alloy of gold and at least one white metal (usually nickel, silver, or palladium).
Like yellow gold, the purity of white gold is given in karats.
Platinum Alloy
Platinum is one of the rarest of the precious metals. Naturally white, platinum will not fade or tarnish – keeping its natural white colour forever. Platinum is also a very strong metal. Its purity makes it hypo-allergenic and ideal for those with sensitive skin. Similar to gold, the purity of the metal is expressed in parts per 1000 and can be identified through its hallmark.
Platinum jewellery is marked with one of the following: Platinum, Pt, Pt950, Plat, Plat 950. The standard is 95% purity.
Annealing
Heating and cooling process to make metal brittle.
It restores its malleability and ductility, enabling you work it again.
Annealing is also use for changing the color of Colored Diamonds.
It restores its malleability and ductility, enabling you work it again.
Annealing is also use for changing the color of Colored Diamonds.
Assay
An assay is a test of the purity of an alloy in UK.
Asterism
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Asterism refers to the presence of a star-shaped light reflection on the surface of gem rough cut as cabochons. The source of this effect is the presence of inclusions of foreign minerals which reflect the light in a star-shaped way.
Rubies and sapphires, cut as cabochons, usually show 6-ray stars indicative of their symmetry, and sometimes 12-ray ones. Other gemstones, such as garnets, may have 4-ray stars. |
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Birthstone
Since ancient times Birthstones (gemstones) have been believed by ancients to possess powers of healing, protection, success, good luck, affections, good overall health etc.
Birthstones are thought to have first become popular in the country of Poland during the 15th or 16th century. It is thought that originally, because the powers of a birthstone are heightened during it’s corresponding month, that they were originally worn by everyone each month
The Traditional Birthstone list - is a compilation of birthstones used in different societies dating back to the 15th century and the traditional ancient Hebrew birthstone.
The Modern Birthstone list - originally adopted in 1912 by the American national Association of Jewellers, it is the accepted list of Jewellers of America. is the official list of birthstones in the U.S.
The Mystical and Ayurvedic Birthstone lists - both have roots dating back over a thousand years. The Mystical list is taken from Tibetan origin and the Ayurvedic list is taken from Ayurvedic Indian Medicine.
Birthstones are thought to have first become popular in the country of Poland during the 15th or 16th century. It is thought that originally, because the powers of a birthstone are heightened during it’s corresponding month, that they were originally worn by everyone each month
The Traditional Birthstone list - is a compilation of birthstones used in different societies dating back to the 15th century and the traditional ancient Hebrew birthstone.
The Modern Birthstone list - originally adopted in 1912 by the American national Association of Jewellers, it is the accepted list of Jewellers of America. is the official list of birthstones in the U.S.
The Mystical and Ayurvedic Birthstone lists - both have roots dating back over a thousand years. The Mystical list is taken from Tibetan origin and the Ayurvedic list is taken from Ayurvedic Indian Medicine.
Bracelet
A bracelet is an article of jewellery that is worn around the wrist. When worn as ornaments, bracelets may have a supportive function to hold other items of decoration, such as charms. If a bracelet is a single, inflexible loop, it is often called a bangle. When it is worn around the ankle it is called an ankle bracelet or anklet. Bracelets can be manufactured from metal or any other materials. Platinum, gold or silver jewellery bracelet sometimes contain precious or semi-precious stones.
Brooch
A brooch also known in ancient times as a Fibula; sometimes spelled broach.A brooch is a decorative jewellery item designed to be attached to garments. It is usually made as a gold or silver jewellery or from metal like bronze (Commercial bronze (90% copper and 10% zinc) and Architectural bronze (57% Copper, 3% Lead, 40% Zinc) or some other material.
Brooches are frequently decorated with enamel or with gemstones and may be solely for ornament. The earliest known brooches are from the Bronze Age (3300 BC)
Brooches are frequently decorated with enamel or with gemstones and may be solely for ornament. The earliest known brooches are from the Bronze Age (3300 BC)
Butterflies
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Also known as a scroll.
It is the fitting that attaches to the pin of an earring to hold it in your ear. |
Bezel Setting
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Full Bezel - The center stone is set deep and is fully encircled by metal. Thus, this offers maximum protection to the stone. A full bezel can accommodate any gemstone shape and is used in many kinds of jewellery.
Semi-Bezel - The semi-bezel shows off more of the diamond, while still protecting it. Light can enter through more angles than in the full bezel setting. |
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Brilliant cut
A brilliant is a diamond or other gemstone cut in a particular form with numerous facets so as to have exceptional brilliance.
The original round brilliant-cut was developed by Marcel Tolkowsky in 1919.
The modern round brilliant consists of 58 facets (or 57 if the culet is excluded), ordinarily today cut in two pyramids placed base to base: 33 on the crown (the top half above the middle or girdle of the stone), truncated comparatively near its base by the table, and 25 on the pavilion (the lower half below the girdle), which has only the apex cut off to form the culet, around which 8 extra facets are sometimes added.
In recent decades, most girdles are faceted. Many girdles have 32, 64, 80, or 96 facets; these facets are not counted in the total.
While the facet count is standard, the actual proportions (crown height and angle, pavilion depth, etc.) are not universally agreed upon.
The original round brilliant-cut was developed by Marcel Tolkowsky in 1919.
The modern round brilliant consists of 58 facets (or 57 if the culet is excluded), ordinarily today cut in two pyramids placed base to base: 33 on the crown (the top half above the middle or girdle of the stone), truncated comparatively near its base by the table, and 25 on the pavilion (the lower half below the girdle), which has only the apex cut off to form the culet, around which 8 extra facets are sometimes added.
In recent decades, most girdles are faceted. Many girdles have 32, 64, 80, or 96 facets; these facets are not counted in the total.
While the facet count is standard, the actual proportions (crown height and angle, pavilion depth, etc.) are not universally agreed upon.
C
Cameo
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Cameo is a method of carving, or an object such as an engraved gem, item of jewellery or vessel made in this manner. It nearly always features a raised (positive) relief image; contrast with intaglio, which has a negative image.
Originally, and still in discussing historical work, cameo only referred to works where the relief image was of a contrasting color to the background; this was achieved by carefully carving a piece of material with a flat plane where two contrasting colors met, removing all the first color except for the image to leave a contrasting background.
Cameos are often worn as jewellery, but in ancient times were mainly used for signet rings.
Today the term may be used very loosely for objects with no color contrast, and other, metaphorical, terms have developed, such as cameo appearance.
This derives from another generalized meaning that has developed, the cameo as an image of a head in an oval frame in any medium, such as a photograph.
Carving
Carving is the act of using tools to shape something from a material by scraping away portions of that material. The technique can be applied to any material that is solid enough to hold a form even when pieces have been removed from it, and yet soft enough for portions to be scraped away with available tools.
Carat
The carat is a unit of mass equal to 200 miligram (mg)
1 carat = 200 miligram (mg) = 0.2 gram
The word came to English from French, from Italian carato, which came from Arabic qīrāṭ .The Arabic qīrāṭ was a very small unit of weight defined by reference to a small seed. Qīrāṭ entered Arabic from Greek kerátion meaning “carob seed”.
In past centuries, different countries each had their own carat unit, all roughly equivalent to the mass of a carob seed, though the carob seed itself was not used as the standard reference point for the weight.
These units were often used for weighing gold.
The current definition, sometimes known as the metric carat, was adopted in 1907 at the Fourth General Conference on Weights and Measures, and soon in many countries around the world.
The carat is divisible into one hundred points.
The term carat (Karat) is also used for the standard of gold and gold alloys but is not a weight measure (ct, kt, K). Pure gold has 24K, which means 24/24 gold shares or 100% gold.
1 carat = 200 miligram (mg) = 0.2 gram
The word came to English from French, from Italian carato, which came from Arabic qīrāṭ .The Arabic qīrāṭ was a very small unit of weight defined by reference to a small seed. Qīrāṭ entered Arabic from Greek kerátion meaning “carob seed”.
In past centuries, different countries each had their own carat unit, all roughly equivalent to the mass of a carob seed, though the carob seed itself was not used as the standard reference point for the weight.
These units were often used for weighing gold.
The current definition, sometimes known as the metric carat, was adopted in 1907 at the Fourth General Conference on Weights and Measures, and soon in many countries around the world.
The carat is divisible into one hundred points.
The term carat (Karat) is also used for the standard of gold and gold alloys but is not a weight measure (ct, kt, K). Pure gold has 24K, which means 24/24 gold shares or 100% gold.
Chatoyancy - cat's eye effect
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In gemology, chatoyancy , or chatoyance, is an optical reflectance effect seen in certain gemstones.
Coined from the French "œil de chat," meaning "cat's eye," chatoyancy arises either from the fibrous structure of a material, as in tiger eye quartz, or from fibrous inclusions or cavities within the stone, as in cat's eye chrysoberyl. The effect can be likened to the sheen off a spool of silk: The luminous streak of reflected light is always perpendicular to the direction of the fibres.
For jewellery a gemstone to show this effect best, it must be cut in cabochon, with the fibers or fibrous structures parallel to the base of the finished stone. Faceted stones are less likely to show the effect well. Gem species known for this phenomenon include the aforementioned quartz, chrysoberyl, beryl (especially var. aquamarine), tourmaline, apatite, moonstone and scapolite.
Cuts of Gemstones - Asscher Cut, Baguette Cut, Briolette Cut, Cabochon Cut, Cushion Cut, Emerald Cut, Heart Cut, Marquise Cut, Octagon Cut, Oval Cut, Pear Cut, Princess Cut, Radiant Cut, Round Cut, Trillion Cut
Round Cut
Asscher Cut
Marquise Cut
Briolette Cut
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Oval Cut
Baguette Cut
Radiant Cut
Trillion Cut
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Pear Cut
Emerald Cut
Octagon Cut
Cabochon Cut
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Heart Cut
Cushion Cut
Princess Cut
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Crystal healing
Crystal healing is an alternative medicine technique which uses stones and crystals for healing purposes.
The crystals are mainly placed on specific areas of the body called "chakras".
Chakra is a Hindu term meaning "spiritual energy".
There are believed to be seven basic energy centres in the body, each having a specific color associated with it. Some crystal healers place the same color crystals as the color of the chakras on the person to enhance the flow of energy.
Crystals are said to direct the flow of energy to the person in a particular part of the body and bring balance to their energy. Ultimately they are used to cleanse the person from bad or negative energy which is believed can Crystal Healing the cause of an illness. Clearing out the bad spiritual energy is believed to alleviate the physical ailment. Crystals are used for physical, mental, emotional and spiritual healing.
Crystals have been used for healing since ancient times by many different cultures. It is a holistic therapy which means the focus is on the individual as a whole, rather than on physical symptoms alone.
The aim of crystal healing is to restore wholeness, balance and health on levels of emotions, mind, spirit as well as the physical body.
This is why crystal healing is considered complementary to regular medicines and not an alternative.
Crystal healing often involves some form of change in a persons well being. It may be through the relief of stress and tensions, through revitalization, relaxation or establishing a greater amount of peace and harmony.
Crystal healers are not permitted or trained to diagnose physical ailments. They do however assess the condition of the bio-magnetic field of a client before choosing appropriate crystals to help bring it back into balance and harmony. Since the state of the bio-magnetic field relates to and influences the state of the physical body, this process will help activate, support and often accelerate the natural self-healing processes.
The bio-magnetic field, also known as the electro-magnetic field or aura, has been discussed and contemplated within the realm of healing and philosophy for thousands of years. It is only fairly recently that science has proven that it must exist around every physical body and organism, thereby helping with among other things, to validate crystal healing.
The crystals are mainly placed on specific areas of the body called "chakras".
Chakra is a Hindu term meaning "spiritual energy".
There are believed to be seven basic energy centres in the body, each having a specific color associated with it. Some crystal healers place the same color crystals as the color of the chakras on the person to enhance the flow of energy.
Crystals are said to direct the flow of energy to the person in a particular part of the body and bring balance to their energy. Ultimately they are used to cleanse the person from bad or negative energy which is believed can Crystal Healing the cause of an illness. Clearing out the bad spiritual energy is believed to alleviate the physical ailment. Crystals are used for physical, mental, emotional and spiritual healing.
Crystals have been used for healing since ancient times by many different cultures. It is a holistic therapy which means the focus is on the individual as a whole, rather than on physical symptoms alone.
The aim of crystal healing is to restore wholeness, balance and health on levels of emotions, mind, spirit as well as the physical body.
This is why crystal healing is considered complementary to regular medicines and not an alternative.
Crystal healing often involves some form of change in a persons well being. It may be through the relief of stress and tensions, through revitalization, relaxation or establishing a greater amount of peace and harmony.
Crystal healers are not permitted or trained to diagnose physical ailments. They do however assess the condition of the bio-magnetic field of a client before choosing appropriate crystals to help bring it back into balance and harmony. Since the state of the bio-magnetic field relates to and influences the state of the physical body, this process will help activate, support and often accelerate the natural self-healing processes.
The bio-magnetic field, also known as the electro-magnetic field or aura, has been discussed and contemplated within the realm of healing and philosophy for thousands of years. It is only fairly recently that science has proven that it must exist around every physical body and organism, thereby helping with among other things, to validate crystal healing.
Crown
The crown is the upper portion of a gemstone that begins just above the girdle. The term 'table' is used to describe the flat top of the crown. The crown of a gemstone is typically raised, though some crowns may be cut very high, flat or even concave. In round and oval stones, the crown of a gemstone consists of 'star facets', 'bezel facets' and 'upper-girdle' facets.
Star facets are the facets that surround the main table facet, they are typically triangular in shape.
Upper-girdle facets, also known as the 'upper-halves', are facets just above the stone's girdle and are also usually triangular.
The bezel facets, known as the 'crown mains', are the full four-sided facets between the upper-girdle and star facets.
Star facets are the facets that surround the main table facet, they are typically triangular in shape.
Upper-girdle facets, also known as the 'upper-halves', are facets just above the stone's girdle and are also usually triangular.
The bezel facets, known as the 'crown mains', are the full four-sided facets between the upper-girdle and star facets.
Culet
The culet (pronounced kyoo-lit) of a diamond is the tiny point at the base of the pavilion, where the facets of the pavilion meet.
Channel setting
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A channel setting is a type of mounting in which gemstones are set into a channel made from two metal strips.
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D
Dispersion
The most familiar example of dispersion is probably a rainbow, in which dispersion causes the spatial separation of a white light into components of different wavelengths (different colors).
Dispersion is most often described for light waves, but it may occur for any kind of wave such as sound waves.
In gemology, dispersion is the difference in the refractive index of a material at the B and G Fraunhofer wavelengths of 686.7 nm and 430.8 nm and is meant to express the degree to which a prism cut from the gemstone shows "fire", or color.
Dispersion is a material property.
Fire depends on the dispersion, the cut angles, the lighting environment, the refractive index, and the viewer.
Dispersion is most often described for light waves, but it may occur for any kind of wave such as sound waves.
In gemology, dispersion is the difference in the refractive index of a material at the B and G Fraunhofer wavelengths of 686.7 nm and 430.8 nm and is meant to express the degree to which a prism cut from the gemstone shows "fire", or color.
Dispersion is a material property.
Fire depends on the dispersion, the cut angles, the lighting environment, the refractive index, and the viewer.
Dichroism
The original meaning of dichroic, from the Greek dikhroos, two-colored.
In optics, a dichroic material is either one which causes visible light to be split up into distinct beams of different wavelengths (colors) (not to be confused with dispersion), or one in which light rays having different polarization are absorbed by different amounts.
In simple words, this is the property of some crystals and solutions such that it exhibits two different colors when viewed from two different directions under transmitted light.
In optics, a dichroic material is either one which causes visible light to be split up into distinct beams of different wavelengths (colors) (not to be confused with dispersion), or one in which light rays having different polarization are absorbed by different amounts.
In simple words, this is the property of some crystals and solutions such that it exhibits two different colors when viewed from two different directions under transmitted light.
E
Engraved gem
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An engraved gem also known as "hard-stone carvings" and similar terms, is a small gemstone, usually semi-precious,that has been carved, in the Western tradition normally with images or inscriptions only on one face.
The engraving of gemstones was a major luxury art form in the ancient world, and an important one in some later periods often used gold or silver jewellery.
Strictly speaking, engraving means carving in intaglio, with the design cut into the flat background of the stone, but relief carvings, with the design projecting out of the background as in nearly all cameos, are also covered by the term. The activity is also called gem carving, and the artists gem-cutters.
References to antique gems, and intaglios in a jewellery context, will almost always mean carved gems.
The engraving of gemstones was a major luxury art form in the ancient world, and an important one in some later periods often used gold or silver jewellery.
Strictly speaking, engraving means carving in intaglio, with the design cut into the flat background of the stone, but relief carvings, with the design projecting out of the background as in nearly all cameos, are also covered by the term. The activity is also called gem carving, and the artists gem-cutters.
References to antique gems, and intaglios in a jewellery context, will almost always mean carved gems.
Earrings and Studs
Studs Earrings
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Traditional Earrings are jewellery attached to the ear through a piercing in the earlobe or some other external part of the ear (except in the case of clip earrings, which clip onto the lobe).
Earrings are worn by both sexes. In western cultures, earrings have traditionally been worn primarily by women, although in recent decades, ear piercing has also become popular among men in North America, Europe, Asia and Africa. Earring jewellery components may be made of any number of materials including silver and gold. |
Engagement ring
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Especially in Western cultures, an engagement ring is a jewellery ring indicating that the person wearing it is engaged to be married.
Engagement rings are traditionally metal or precious metal gold or silver jewellery ring worn only by women, and rings can set with precious stone or gemstones. In other cultures men and women usually wear matching rings, which can be plain. In some cultures, engagement rings are also used as wedding rings. |
GGEternity ring
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An eternity ring is a narrow ring with a line of diamonds or other gemstones running all the way round. The unbroken circle symbolizing eternity. A husband often gives it to his wife after a number of years of marriage or the birth of a child to show that the commitment made at their wedding is as strong as ever.
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F
Fabergé
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Peter Carl Fabergé also known as Carl Gustavovich Fabergé in Russia (May 30, 1846 – September 24, 1920) was a Russian jeweller of French origin, best known for the famous Faberge eggs , made in the style of genuine Easter eggs, but using precious metals and gemstones rather than more mundane materials.
Filigree
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Filigree (formerly written filigrann or filigrane) is a delicate kind of jewel work made with twisted threads usually of gold and silver or stitching of the same curving motifs.
It often suggests lace, and in recent centuries remains popular in Indian and other Asian metalwork, and French from 1660 to the late 19th century. It should not be confused with ajoure gold or silver jewellery; while both have many open areas, filigree involves threads being soldered together to form an object and ajoure involves holes being punched, drilled or cut through an existing piece of metal.
The word, often thought derived from the Latin filum, thread, and granum, grain, is not found in Du Cange ( Charles du Fresne, sieur du Cange or Ducange (1610 – 688) was a distinguished philologist and historian of the Middle Age and Bizantium), and is indeed of modern origin.
According to Prof. Skeat it derives from the Spanish filigrana, from "filar", to spin, and grano, the grain or principal fibre of the material.
Facet
A flat cut or polished face on a gemstone.
Faux
A term meaning imitation. For example, "faux pearls" is often used to describe simulated pearls.
Fluorescence
The visible or invisible radiation produced from certain substances as a result of incident radiation of a shorter wavelength such as X-rays or ultraviolet light.
Fluorescence is the visible light some gemstones emit when they are exposed to invisible ultraviolet (UV) rays.
In natural diamonds, blue is the most common color of fluorescence, but other colors may be visible.
On a GIA Diamond Grading Report, fluorescence refers to the strength, or intensity, of the diamond’s reaction to long-wave UV, which is an essential component of daylight.
Fluorescence is the visible light some gemstones emit when they are exposed to invisible ultraviolet (UV) rays.
In natural diamonds, blue is the most common color of fluorescence, but other colors may be visible.
On a GIA Diamond Grading Report, fluorescence refers to the strength, or intensity, of the diamond’s reaction to long-wave UV, which is an essential component of daylight.
G
Gemstone or gem
A gemstone or gem (also called a precious or semi-precious stone, or jewel) is a piece of mineral, which in cut and polished form is used to make jewellery or other adornments.
However certain rocks, (such as lapis lazuli) and organic materials (such as amber or jet) are not minerals, but are still used for jewellery, mostly for silver jewellery, and are therefore often considered to be gemstones as well.
Most gemstones are hard, but some soft minerals are used in jewellery because of their lustre or other physical properties that have aesthetic value.
Apart from jewellery, from earliest antiquity until the 19th century engraved gems and hard stone carvings such as cups were major luxury art forms; the carvings of Carl Fabergé were the last significant works in this tradition.
However certain rocks, (such as lapis lazuli) and organic materials (such as amber or jet) are not minerals, but are still used for jewellery, mostly for silver jewellery, and are therefore often considered to be gemstones as well.
Most gemstones are hard, but some soft minerals are used in jewellery because of their lustre or other physical properties that have aesthetic value.
Apart from jewellery, from earliest antiquity until the 19th century engraved gems and hard stone carvings such as cups were major luxury art forms; the carvings of Carl Fabergé were the last significant works in this tradition.
Gems that require Special Care
Peridot:
It is a little low in hardness so care must be taken in setting it, wearing it and cleaning it.
Tanzenite:
Same special care as for peridot, for same reasons.
Emerald:
A high value fragile gem. Not recommended for everyday wear. Care must be taken in setting it, wearing it and cleaning it.
Pearls:
Will be attacked by perfume (before drying) and prolonged exposure to perspiration. Must be cleaned properly and stored properly.
Decorative Stones:
These are stones that are not single crystals and hence are porous. They should not be washed with soap as this will penetrate and change their appearance, egz Lapis, Agates, Turquoise.
Diamond, Topaz, Kunzite:
A sharp blow, in a certain direction, can cause the stone to break (cleave).
It is a little low in hardness so care must be taken in setting it, wearing it and cleaning it.
Tanzenite:
Same special care as for peridot, for same reasons.
Emerald:
A high value fragile gem. Not recommended for everyday wear. Care must be taken in setting it, wearing it and cleaning it.
Pearls:
Will be attacked by perfume (before drying) and prolonged exposure to perspiration. Must be cleaned properly and stored properly.
Decorative Stones:
These are stones that are not single crystals and hence are porous. They should not be washed with soap as this will penetrate and change their appearance, egz Lapis, Agates, Turquoise.
Diamond, Topaz, Kunzite:
A sharp blow, in a certain direction, can cause the stone to break (cleave).
Grain
1 grain = 64.79891 milligrams
A grain is a unit of mass that is based upon the mass of a single seed of a typical cereal (cereals, grains, or cereal grains are grasess Historically, in Europe , the average masses of wheat and barley grain were used to define units of mass, with the troy grain based on barley. Since 1958, the grain or troy grain (Symbol: gr) measure has been redefined on the basis of the base unit of mass of the International System of Units as precisely 64.79891 milligrams. Thus, there are precisely 7,000 grains per avoirdupois pound in the Imperial and US customary units. The grain is also used to express the mass measure for pearls and diamonds—the pearl grain and the metric grain—are equal to 1⁄4 of a (metric) carat, i.e. 50mg (0.77gr).
In the USA. the grain is used to measure the mass of bullets, gunpowder and smokeless powder. The grain is used to weigh fencing equipment, including the foil. In archery, the grain is used to weigh arrows and arrow parts.
A grain is a unit of mass that is based upon the mass of a single seed of a typical cereal (cereals, grains, or cereal grains are grasess Historically, in Europe , the average masses of wheat and barley grain were used to define units of mass, with the troy grain based on barley. Since 1958, the grain or troy grain (Symbol: gr) measure has been redefined on the basis of the base unit of mass of the International System of Units as precisely 64.79891 milligrams. Thus, there are precisely 7,000 grains per avoirdupois pound in the Imperial and US customary units. The grain is also used to express the mass measure for pearls and diamonds—the pearl grain and the metric grain—are equal to 1⁄4 of a (metric) carat, i.e. 50mg (0.77gr).
In the USA. the grain is used to measure the mass of bullets, gunpowder and smokeless powder. The grain is used to weigh fencing equipment, including the foil. In archery, the grain is used to weigh arrows and arrow parts.
Girdle
The girdle is the widest point of the circumference of a gemstone. It is the perimeter of the stone that separates the gem's pavilion from its crown. It is also usually the point where a stone is held when it is being examined. Girdles may be described as "thin" or "thick", or they may be more precisely specified as a percentage of the stone's diameter.
Gypsy Setting
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The difference between a bezel setting and gypsy setting is that the metal on a bezel setting will almost seem to come up over the gemstone, whereas in a gypsy setting the gemstone is sunk into the metal, so the gemstone sits below the surface of the metal. A gypsy setting is also known as a flush setting.
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Hard stone carving
(Stone carving is an ancient activity where pieces of rough natural stone are shaped by the controlled removal of stone)
Hard-stone carving is a general term in art history and archaeology for the carving for artistic purposes of semi-precious stones, also known as gemstones, such as (jade, rock crystal clear quartz), agate, onyx, jasper, serpentine or carnelian, and for an object made in this way.
Normally the objects are small, and the category overlaps with gold and silver jewellery or sculpture.
Hard-stone carving is a general term in art history and archaeology for the carving for artistic purposes of semi-precious stones, also known as gemstones, such as (jade, rock crystal clear quartz), agate, onyx, jasper, serpentine or carnelian, and for an object made in this way.
Normally the objects are small, and the category overlaps with gold and silver jewellery or sculpture.
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Intaglio
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Intaglio refers to a number of techniques in art, applied to many different materials, which all have in common that the image is created by cutting, carving or engraving into a flat surface, as opposed to a relief, where the image is what is left when the background has been cut away to leave the image above the background. The term may also refer to objects made using these techniques.
Iridescence
This is an optical phenomenon in which the hue on the surface of the stone changes according to the angle from which the surface is viewed. A similar phenomenon may be seen on the surface of soap bubbles and on butterfly wings. The word is derived in part from the Greek word iris meaning 'rainbow', from the goddess Iris the personification of the rainbow in Greek mythology.
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Jewellery
Jewellery (British English) or jewelry (American English) is a form of personal adornment, manifesting itself as necklace,rings, brooches, earrings and bracelets. Omitting gold and silver jewellery, jewellery may be made from any material, usually gemstones, precious metals or shells. Factors affecting the choice of materials include cultural differences and the availability of the materials.
The word jewellery is derived from the word jewel, which was Anglicised from the Old French "jouel". Jewellery is one of the oldest forms of body adornment; recently-found 100,000-year-old.The first pieces of jewellery were made from natural materials , such as bone, animal teeth, shell, wood and stone. Some jewellery throughout the ages may have specifically been as an indication of a social group. Due to its personal nature and its indication of social class, some cultures established traditions of burying the dead with their jewellery.
Jewellery has been made to adorn nearly every body part. High-quality platinum, gold and silver jewellery is made with gemstones .
In addition, there is the less costly costume jewellery, made from lower value materials and mass-produced.
The word jewellery is derived from the word jewel, which was Anglicised from the Old French "jouel". Jewellery is one of the oldest forms of body adornment; recently-found 100,000-year-old.The first pieces of jewellery were made from natural materials , such as bone, animal teeth, shell, wood and stone. Some jewellery throughout the ages may have specifically been as an indication of a social group. Due to its personal nature and its indication of social class, some cultures established traditions of burying the dead with their jewellery.
Jewellery has been made to adorn nearly every body part. High-quality platinum, gold and silver jewellery is made with gemstones .
In addition, there is the less costly costume jewellery, made from lower value materials and mass-produced.
Jewellery Items TYPES
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Bracelet
Bangle
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Bracelet and Bangle :
A bracelet is an article of jewellery that is worn around the wrist. When worn as ornaments, bracelets may have a supportive function to hold other items of decoration, such as charms. If a bracelet is a single, inflexible loop, it is often called a bangle. When it is worn around the ankle it is called an ankle bracelet or anklet. Bracelets can be manufactured from metal or any other materials. Platinum, gold or silver jewellery bracelet sometimes contain precious or semi-precious stones |
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Brooch:
A brooch also known in ancient times as a Fibula; sometimes spelled broach, is a decorative jewellery item designed to be attached to garments. It is usually made of metall, often silver or gold but sometimes bronze (Commercial bronze (90% copper and 10% zinc) and Architectural bronze (57% Copper, 3% Lead, 40% Zinc) or some other material. Brooches are frequently decorated with enamel or with gemstones and may be solely for ornament. The earliest known brooches are from the Bronze Age (3300 BC) |
Studs Earrings
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Earrings:
Traditional Earrings are jewellery attached to the ear through a piercing in the earlobe or some other external part of the ear (except in the case of clip earrings, which clip onto the lobe). Earrings are worn by both sexes. In western cultures, earrings have traditionally been worn primarily by women, although in recent decades, ear piercing has also become popular among men in North America, Europe, Asia and Africa. Earring jewellery components may be made of any number of materials including silver and gold. |
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Locket:
A locket is a pendant that opens to reveal a space used for storing a photographs or other small item such as a curl of hair. Lockets are usually given to loved ones on holidays such as Valentine's Day and occasions such as infant baptism or christening, weddings and, most noticeably during the Victorian Age. Lockets are generally worn on chains around the neck and often hold a photo of the person who gave the locket, or they could form part of a charm bracelet. They come in many shapes such as ovals, hearts and circles and are usually made of precious metals such as gold and silver befitting their status as decorative jewellery. Another kind of locket is/was made in a filigree style with a small cushion in the center to which a few drops of perfume should be added, perfume lockets were popular in eras when personal hygiene was restricted and sweet smelling perfume was used to mask the odour of a person or their companions. |
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Necklace:
A necklace is an article of jewellery which is worn around the neck Necklaces are frequently formed from a metal or jewellery precious metals , often attached to a locket or pendant. Necklaces can also be manufactured with cloth, and they sometimes contain rock (particularly gems), wood, and/or shells with different shapes and sizes. |
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Pendant:
A pendant (from Old French) is a hanging jewellery object, generally attached to a necklace chain or an earring. Pendants can have several functions: Ornamentation, Identification, Protection (amulets), Self-affirmation, Ostentation, Award. |
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Engagement ring:
Especially in Western cultures, an engagement ring is a jewellery ring indicating that the person wearing it is engaged to be married. Engagement rings are traditionally metal or precious metal jewellery ring worn only by women, and rings can set with precious stone or gemstones. In other cultures men and women usually wear matching rings, which can be plain. In some cultures, engagement rings are also used as wedding rings. |
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Eternity ring:
An eternity ring is a narrow ring with a line of diamonds or other gemstones running all the way round. The unbroken circle symbolizing eternity. A husband often gives it to his wife after a number of years of marriage or the birth of a child to show that the commitment made at their wedding is as strong as ever. |
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Wedding Ring:
A wedding ring or wedding band is a metal or precious metal gold or silver jewellery ring indicating the wearer is married. Depending on the local culture, it is worn on the base of the right or the left ring finger. The custom of wearing such a ring has spread widely beyond its origin in Europe. Originally worn by wives only, wedding rings became customary for both husbands and wives during the 20th century. Unlike other jewellery the wedding ring is worn day and night and rarely removed. The fourth digit or ring finger of the hand has become the customary place to wear a wedding ring in much of the world. It stems from a 16th-century Tudor belief (Tudor dynasty or House of Tudor ruled the Kingdom of England and Kingdom of Ireland, from 1485 until 1603. Its first monarch was Henry Tudor.) that the left-handed ring finger was connected by a vein directly to the heart; thus, wearing a ring on the third finger demonstrated that the wearer was in a relationship. |
Jewellery Valuation and Jewellery Appraisal
The difference between a Jewellery Valuation and Jewellery Appraisal:
Valuations are required when a definitive value is needed. Reasons for this include obtaining finance from a lending institution or establishing the value for an insurance purposes. A Court may also order that a valuation be obtained as part of the process of resolving a dispute.
Appraisals are only intended as a guide to pricing. Appraisals are estimated by knowledge of the local market and recent sale prices and should only ever be used as an estimate of price. They are not definitive and have no legal standing.
Valuations are required when a definitive value is needed. Reasons for this include obtaining finance from a lending institution or establishing the value for an insurance purposes. A Court may also order that a valuation be obtained as part of the process of resolving a dispute.
Appraisals are only intended as a guide to pricing. Appraisals are estimated by knowledge of the local market and recent sale prices and should only ever be used as an estimate of price. They are not definitive and have no legal standing.
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Lace
Lace is an openwork fabric , patterned with open holes in the work, made by machine or by hand. The holes can be formed via removal of threads or cloth from a previously woven fabric, but more often open spaces are created as part of the lace fabric.
Lace-making is an ancient craft, and a true lace was not made until the late 15th and early 16th centuries.
A true lace is created when a thread is looped, twisted or braided to other threads independently from a backing fabric.Originally linen, silk, gold, or silver threads were used.
Now lace is often made with cotton thread or synthetic fiber.
A few modern artists make lace with a fine copper or silver wire instead of thread.
Lace-making is an ancient craft, and a true lace was not made until the late 15th and early 16th centuries.
A true lace is created when a thread is looped, twisted or braided to other threads independently from a backing fabric.Originally linen, silk, gold, or silver threads were used.
Now lace is often made with cotton thread or synthetic fiber.
A few modern artists make lace with a fine copper or silver wire instead of thread.
Early bobbin lace in gold and silver thread, c. 1570.
Weiss Gallery catalogue A Noble Visage: Early Portraiture 1545–1660 |
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Locket
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A locket is a pendant that opens to reveal a space used for storing a photographs or other small item such as a curl of hair. Lockets are usually given to loved ones on holidays such as Valentine's Day and occasions such as infant baptism or christening, weddings and, most noticeably during the Victorian Age.
Lockets are generally worn on chains around the neck and often hold a photo of the person who gave the locket, or they could form part of a charm bracelet. They come in many shapes such as ovals, hearts and circles and are usually made of precious metals such as gold and silver befitting their status as decorative jewellery. Another kind of locket is/was made in a filigree style with a small cushion in the center to which a few drops of perfume should be added, perfume lockets were popular in eras when personal hygiene was restricted and sweet smelling perfume was used to mask the odor of a person or their companions. |
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Mineral and mineraloid
Mineral:
A mineral is an element or chemical compound that is normally crystalline and that has been formed as a result of geological process.
Mineraloid:
A mineraloid is a mineral-like substance that does not demonstrate crystallinity. Mineraloids possess chemical compositions that vary beyond the generally accepted ranges for specific minerals.
For example, obsidian is an amorphous glass and not a crystal. Jet is derived from decaying wood under extreme pressure. Opal is another mineraloid because of its non-crystal nature.
Pearls, considered by some to be a mineral because of the presence of calcium carbonate crystals within their structure, would be better considered a mineraloid because the crystals are bonded by an organic material and there is no definite proportion of the components.
A mineral is an element or chemical compound that is normally crystalline and that has been formed as a result of geological process.
Mineraloid:
A mineraloid is a mineral-like substance that does not demonstrate crystallinity. Mineraloids possess chemical compositions that vary beyond the generally accepted ranges for specific minerals.
For example, obsidian is an amorphous glass and not a crystal. Jet is derived from decaying wood under extreme pressure. Opal is another mineraloid because of its non-crystal nature.
Pearls, considered by some to be a mineral because of the presence of calcium carbonate crystals within their structure, would be better considered a mineraloid because the crystals are bonded by an organic material and there is no definite proportion of the components.
Minerals to Gemstones
Mohs scale
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Sclerometer also known as the Turner-sclerometer, is an instrument used by to measure the scratch hardness of materials.
It was invented by Prof. Thomas Turner in 1896. A sclerometer measures hardness with the use of a standardized diamond head which is dragged across the material being tested. Hardness is determined by finding out how much pressure is needed to create a visible scratch. |
The Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer material.
It was created in 1812 by the German mineralogist Friedrich Mohs.
The Mohs scale of mineral hardness is based on the ability of one natural minerals sample of matter to scratch another. For example, corundum (9) is twice as hard as topaz (8), but diamond (10) is almost four times as hard as corundum.
The table below shows comparison with absolute hardness measured by a scelerometer.
● 1 Talc Absolute hardness - 1
● 2 Gypsum Absolute hardness - 3
● 3 Calcite Absolute hardness - 9
● 4 Fluorite Absolute hardness - 21
● 5 Apatite Absolute hardness - 48
● 6 Feldspar Absolute hardness - 72
● 7 Quartz Absolute hardness - 100
● 8 Topaz Absolute hardness - 200
● 9 Corundum Absolute hardness - 400
● 10 Diamond Absolute hardness - 1600
Intermediate hardness :
• 0.2–0.3 caesium, rubidium
• 0.5–0.6 potassium lithium, sodium
• 1.0 talc, graphite, plastic, pencil lead
• 1.5 strontium, gallium, indium, barium, indium, tin, thallium, lead
• 2.0 calcium, selenium, tellurium, boron nitride, cadmium, sulphur, bismuth, gypsum, alabaster, rock salt
• 2.5 to 3 gold, silver, aluminium, zinc, magnesium, cerium, lanthanum, mercury, salt, amber, ivory, pearl, jet
• 3.0 copper, dentine, calcite, arsenic, antimony, thorium, limestone, shell, bronze, coral
• 3..0-3.5 barite
• 3.5-4.0 malachite, azarite,
• 4.0 iron, nickel, fluorite
• 4.0-4.5 platinum, steel
• 5.0 cobalt,apatite, zirconium, tooth enamel, palladium, apatite
• 5.5 molybdenum, beryllium, hafnium, rhodonite
• 6.0 titanium, manganese, germanium, niobium, uranium rhodium,
• 6.0-7.0 silicon, glass, fused quartz, iridium, tantalum, iron pyrite, ruthenium, tanzanite, fire opal, nephrite, iridium, konzite, peridot,
• 7.0 vanadium, quartz, osmium, rhenium, boodstone, flint, chalcedony, tiger's eye
• 7.5-8.0 tungsten hardened steel, emerald
• 8.0 cubic zirconia , topaz
• 8.5 chromium, chrysoberyl
• 9.0-9.5 corundum, carborundum, tangsten carbide, silicon carbide, titanium carbide, stishovite, sapphire,
ruby, moisanite
• 9.5–10.0 rhenium diboride, tantalum carbide, titanium diboride, boron, corborundum
• 10.0 diamond, fullerite
• >10 hyper diamond, aggregated diamond
➢ Aggregated diamond nanorods, or ADNRs (also called a hyper diamond), are a nano crystalline form of diamond reported to be the hardest and least compressible known material. ADNRs are produced by compressing fullerite powder — a solid form of allotropic carbon fullerene. Extreme hardness of nano diamonds was reported by researchers in the 1990s.The material is a series of interconnected diamond nanorods, with diameters of between 5 and 20 nanometres and lengths of around 1 micrometre each.
Mabe pearls
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Formed when a half-bead is cemented to the mollusc's inner shell. The mollusc covers the half bead with nacre and when the shell is cut off, the bead is exposed at the back. The bead is removed, the pearl cleaned (to prevent deterioration) and the remaining hole filled with paste, wax or sometimes with another bead and then covered with a mother-of-pearl backing. Mabe pearls must only be used in closed-back settings. Also referred to as a half-pearl or cultured blister pearl.
Mother of Pearl
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The smooth, hard pearly lining on the interior of oyster and mollusc shells, famous for buttons and small decorative objects. It is the same substance as nacre which forms pearls.
Nacre, also known as mother-of-pearl, is a crystalline substance that creates the iridescent visual effect attributed to pearls. Nacre is an organic substance secreted by mollusks over an intruding irritant or implanted nucleus. It is a strong and resilient material that is lightweight and transparent, allowing light to pass through its surface, creating a subtle glow on the pearls surface. |
Millegrain
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A technique was developed in the late 19th century as a textural effect to metal work on the edges or bezels of jewelry. That technique is referred to as millegrain (or mille grain or even milegrain).
From the French word mille for a thousand, and from grain as the same meaning in English, it refers to what appears to be thousands of tiny beads upon a metal precipice or edge. |
Mallorca
A well-known type of imitation pearls from the Spanish island of the same name. Also known as Majorcan pearls, they are quite popular in the USA.
Many people believe them to be real pearls when, in fact, they are high quality imitations.
Many people believe them to be real pearls when, in fact, they are high quality imitations.
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Nacre
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Nacre, also known as mother-of-pearl, is a crystalline substance that creates the iridescent visual effect attributed to pearls. Nacre is an organic substance secreted by mollusks over an intruding irritant or implanted nucleus.
It is a strong and resilient material that is lightweight and transparent, allowing light to pass through its surface, creating a subtle glow on the pearl?s surface. Nacre is composed primarily of crystallized calcium carbonate (CaCo3) and conchiolin |
Conchiolin is a dark-colored substance secreted by the mollusk during the initial phases of pearl formation. Conchiolin is an organic protein that acts as a form of glue or adhesive. Generally it is the first layer deposited by the pearl sac.
Conchiolin surrounds the bead nucleus or irritant and functions as a base coat that will cause the pursuant nacre layers to bind together. The brownish material does not always confine itself to the initial coating, and may be observed throughout the nacreous stratum in cultured pearls that have been cross-sectioned.
Conchiolin surrounds the bead nucleus or irritant and functions as a base coat that will cause the pursuant nacre layers to bind together. The brownish material does not always confine itself to the initial coating, and may be observed throughout the nacreous stratum in cultured pearls that have been cross-sectioned.
Necklace
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A necklace is an article of jewellery which is worn around the neck Necklaces are frequently formed from a metal or jewellery precious metals , often attached to a locket or pendant.
Gold or silver jewellery necklaces often contain precious or semi-precious stones. Necklaces can also be manufactured with cloth, and they sometimes contain rock (particularly gems), wood, and/or shells with different shapes and sizes. |
Navette
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This nickname has become popular as the word itself is an homage to the Navy and the cut has a particular resemblance to a little ship.
Navette cut is the same as the Marquise cut. The Marquise cut originally crafted in the 1700’s when King Louis XV employed a jeweler to create a cut that was reflective of the smile of his mistress. |
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Opalescence
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Opalescence is a type of dichroism where a gem appears yellowish-red in transmitted light and blue in the scattered light perpendicular to the transmitted light.
In simple words, opalescent means changing color like an opal. |
Ounce
The ounce (abbreviated: oz, the old Italian word onza, now spelled oncia) is a unit of mass with several definitions, the most commonly used of which are equal to approximately 28 grams. The ounce is used in a number of different systems, including various systems of mass that form part of the imperial and USA systems. Its size can vary from system to system. The most commonly used ounces today are the International avoirdupois ounce and the international troy ounce.
Summary of ounce units ounce variant equivalent in grams and equivalent in grains.
Name Equivalent in grams Equivalent in grains
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International avoirdupois ounce 28.3495231 437.5
International Gold troy ounce 31.103476 480
Maria Theresa ounce 28.0668 433.137
Dutch metric ounce 100 1 ,543.236
Chinese metric ounce 50 771.618
Apothecaries' ounce - it divides a pound into 12 ounces, an ounce into 8 drachms, and a drachm into 3 scruples or 60 grains.The apothecaries' system of measures is a similar system of volume units based on the fluid ounce.
Today, the troy ounce is used only to express the mass of precious metals such as gold, platinum, palladium or silver.
Summary of ounce units ounce variant equivalent in grams and equivalent in grains.
Name Equivalent in grams Equivalent in grains
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International avoirdupois ounce 28.3495231 437.5
International Gold troy ounce 31.103476 480
Maria Theresa ounce 28.0668 433.137
Dutch metric ounce 100 1 ,543.236
Chinese metric ounce 50 771.618
Apothecaries' ounce - it divides a pound into 12 ounces, an ounce into 8 drachms, and a drachm into 3 scruples or 60 grains.The apothecaries' system of measures is a similar system of volume units based on the fluid ounce.
Today, the troy ounce is used only to express the mass of precious metals such as gold, platinum, palladium or silver.
P
Pleochroism
Pleochroism (from Greek πλέων, pléōn, "more" and χρῶμα, khrôma, "color") is an optical phenomenon in which a substance has different colors when observed at different angles, especially with polarized light.
Polarized light -when something emits light, the waves produced usually have their oscillation moving at all different angles. You can have some oscillating left and right, up and down, at a 45-degree angle, or any angle imaginable. This is what we call unpolarized light, which means that all the light waves have different planes of oscillation. Polarized light is when light passes through a filter and the waves of light are limited to one plane of movement and the rest is absorbed, leaving polarized light to only have one plane of oscillation. The filter has tiny gaps in them that are all parallel to one another, as such only waves oscillating in parallel to the filter will pass through. This will decrease the intensity of the light passing through (intensity being the amount of light present), decreasing it dependent on the angle of the filter and if the light is polarized beforehand.
Pleochroism is an extremely useful tool in mineralogy and gemology for mineral and gem identification, since the number of colors visible from different angles can identify the possible crystalline structure of a gemstone or mineral and therefore help to classify it.
Polarized light -when something emits light, the waves produced usually have their oscillation moving at all different angles. You can have some oscillating left and right, up and down, at a 45-degree angle, or any angle imaginable. This is what we call unpolarized light, which means that all the light waves have different planes of oscillation. Polarized light is when light passes through a filter and the waves of light are limited to one plane of movement and the rest is absorbed, leaving polarized light to only have one plane of oscillation. The filter has tiny gaps in them that are all parallel to one another, as such only waves oscillating in parallel to the filter will pass through. This will decrease the intensity of the light passing through (intensity being the amount of light present), decreasing it dependent on the angle of the filter and if the light is polarized beforehand.
Pleochroism is an extremely useful tool in mineralogy and gemology for mineral and gem identification, since the number of colors visible from different angles can identify the possible crystalline structure of a gemstone or mineral and therefore help to classify it.
Polarized light
When something emits light, the waves produced usually have their oscillation moving at all different angles.
You can have some oscillating left and right, up and down, at a 45-degree angle, or any angle imaginable. This is what we call unpolarized light, which means that all the light waves have different planes of oscillation.
Polarized light is when light passes through a filter and the waves of light are limited to one plane of movement and the rest is absorbed, leaving polarized light to only have one plane of oscillation.
The filter has tiny gaps in them that are all parallel to one another, as such only waves oscillating in parallel to the filter will pass through.
This will decrease the intensity of the light passing through (intensity being the amount of light present), decreasing it dependent on the angle of the filter and if the light is polarized beforehand.
You can have some oscillating left and right, up and down, at a 45-degree angle, or any angle imaginable. This is what we call unpolarized light, which means that all the light waves have different planes of oscillation.
Polarized light is when light passes through a filter and the waves of light are limited to one plane of movement and the rest is absorbed, leaving polarized light to only have one plane of oscillation.
The filter has tiny gaps in them that are all parallel to one another, as such only waves oscillating in parallel to the filter will pass through.
This will decrease the intensity of the light passing through (intensity being the amount of light present), decreasing it dependent on the angle of the filter and if the light is polarized beforehand.
Precious stones
The most precious stones are the diamond, emerald, ruby and sapphire.
In our opinion , alexandrite, demantoid garnet and tanzanite, can be also consider at as precious stones.
In our opinion , alexandrite, demantoid garnet and tanzanite, can be also consider at as precious stones.
Precious metals
Platinum:
Melting point: 1768C Density: 20.1-21.4g/cm3
The first European reference to platinum appears in 1557 in the writings of the Italian humanist Julius Cesar Scaliger as a description of an unknown noble metal found between Darien and Mexico, "which no fire nor any Spanish artifice has yet been able to liquefy."
Its name is derived from the Spanish term platina del Pinto, which is literally translated into "little silver of the Pinto River .
Platinum as a pure metal, is silvery-white, lustrous, ductile, and malleable.
Platinum finds use in jewellery, usually as a 90–95% combined with iridium, palladium, ruthenium or other alloy.Due to its inertness and shine and does not need to be rhodium plated like white gold does. Platinum is very dense and heavy metal, so a platinum jewellery will feel heavier and more expensive than an 18kt gold jewellery.. Platinum is normally not used in the full range of jewellery.
Gold:
Pure 100% (24 carat or karat) gold is a deep yellow color , soft and very malleable.
For most uses of gold the pure metal is too soft on its own and is therefore hardened by the addition of alloying elements, copper, silver, nickel, palladium and zinc. Gold is of course yellow and the various colours seen such as red, white and green. The final colour and mechanical properties are dependent on the ratios and type of alloys added and can be obtained in a range of colour shades: green (actually a green shade of yellow), pale yellow, yellow, deep yellow, pink/rose, red and white gold.
The colored carat gold alloys range in gold content from 9 to 22 carats (33.3% - 91.6% gold).
Most popular gold grades:
24 ct - stamp 1000. 24ct, 24kt, 24K
Melting point: 1064 C Density: 19.32 g/cm3
(100%)
22 ct – stamp: 916, 22ct. 22 kt, 22K
Melting range: 964-1020 C Density:17,7-17.9 g/cm3
22 carat gold (contain 91.6% pure gold)
18 ct – stamp : 750, 18ct.18kt, 18K.
Melting range: 880-960 C Density: 15.15-15.9 g/cm3
18 carat gold (contain 75.0% pure gold)
14 ct - stamp 583 or 585, 14ct,14kt, 14K.
Melting range: 830-970 C Density: 12.9 to 14.6 g/cm3
14kt gold (contain 58.5% pure gold)
9 ct – stamp: 375, 9ct, 9kt, 9K.
Melting range: 850-900 C Density: 10.9 to 12.7 g/cm3
9kt gold (contain 37.5% pure gold)
White Gold:
White golds for jewellery were developed in the 1920's as a substitute for platinum.
There is 2 basic classes of white golds - the Nickel whites and the Palladium whites.
White gold jewellery is normally electroplated with rhodium which is tarnish resistant and imparts a good white colour
Nickel white gold:
Nickel alloying additions form hard and strong white golds up to 18 carat.
Palladium white gold: They are available in all caratages up to 21 carat. Additions of about 10 -12% palladium to gold impart a good white colour. But palladium is an expensive metal, dearer than gold and it is also a heavy metal. Thus palladium white golds will be more expensive than identical pieces in nickel whites for 2 reasons: firstly, the cost of the palladium and secondly, the impact of density - palladium white golds are denser and so such jewellery will be heavier and also contain more gold. Many commercial palladium white golds only contain about 6-8% palladium plus silver, zinc and copper. Some may even contain some nickel, so a palladium white gold is not necessarily nickel-free.
Red or Rose-coloured gold: Rose-coloured gold is alloyed with copper and is often used to accent white or yellow gold.
Gold Grades hardness:
Choosing jewellery, particularly rings, many people consider the hardness and durability of gold to be used in their ring.
Metal hardness is measured by what is called the Vickers scale where harder metals receive a higher Vickers score than less hard metals.
9kt has a Vickers hardness of 120 and 18kt has a Vickers hardness of 125. This shows 18kt as harder, but the difference is so slight that in practical terms 9kt and 18kt are much the same in terms of hardness.
Another difference that should be considered when comparing 9kt and 18kt, 9kt is more difficult to bend and is a little more springy and therefore a fine 9kt ring may be less likely to bend out of shape than a fine 18kt ring. However, if the ring is of a good sturdy construction neither metal will be likely to bend out of shape.
Palladium:
Melting point: 1554.9 C Density: 12.023 g/cm3
Palladium is a rare transition metal with the symbol (Pd) from the traditional abbreviation for the Latin Argentum. Palladium was originally discovered within platinum ores, and is chemically similar to platinum. Palladium occurs within naturally alloyed gold or platinum, and as a 'free metal.'Like platinum, palladium has a lustrous silver-white colour and it is ideal for use in jewellery. As palladium jewellery is manufactured from 95 – 100% pure palladium, the jewellery is hypo-allergenic. This means that it is the ideal metal for people with sensitive or irritable skin.
Palladium is a very hard metal; in fact, it is 12% harder than platinum. It is also 40% lighter than platinum, a statistic that translates into a significant saving when it comes to purchasing palladium jewellery. Because palladium is a naturally white metal, there is no need to rhodium-plate it and palladium jewellery will keep it’s colour over time.
The price of palladium is fraction of platinum and gold price and when compared to an identically designed platinum or gold jewellery a palladium jewellery will weigh significantly less and will thus cost less.
Silver:
Melting point: 961.78 C Density: 10.49 g/cm3
Silver is a very ductile malleable (slightly harder than gold) with a brilliant white metallic luster that can take a high degree of polish. Among metals, pure silver has the highest thermal conductivity.
Silver jewellery and silverware are traditionally made from sterling silver (standard silver), an alloy of 92.5% silver with 7.5% copper. In the US, only an alloy consisting of at least 92.5% fine silver can be marketed as "silver" stamped 925.
Sterling silver jewellery is often plated with a thin coat of 0.999 fine silver or rhodium to give the item a shiny finish.
Melting point: 1768C Density: 20.1-21.4g/cm3
The first European reference to platinum appears in 1557 in the writings of the Italian humanist Julius Cesar Scaliger as a description of an unknown noble metal found between Darien and Mexico, "which no fire nor any Spanish artifice has yet been able to liquefy."
Its name is derived from the Spanish term platina del Pinto, which is literally translated into "little silver of the Pinto River .
Platinum as a pure metal, is silvery-white, lustrous, ductile, and malleable.
Platinum finds use in jewellery, usually as a 90–95% combined with iridium, palladium, ruthenium or other alloy.Due to its inertness and shine and does not need to be rhodium plated like white gold does. Platinum is very dense and heavy metal, so a platinum jewellery will feel heavier and more expensive than an 18kt gold jewellery.. Platinum is normally not used in the full range of jewellery.
Gold:
Pure 100% (24 carat or karat) gold is a deep yellow color , soft and very malleable.
For most uses of gold the pure metal is too soft on its own and is therefore hardened by the addition of alloying elements, copper, silver, nickel, palladium and zinc. Gold is of course yellow and the various colours seen such as red, white and green. The final colour and mechanical properties are dependent on the ratios and type of alloys added and can be obtained in a range of colour shades: green (actually a green shade of yellow), pale yellow, yellow, deep yellow, pink/rose, red and white gold.
The colored carat gold alloys range in gold content from 9 to 22 carats (33.3% - 91.6% gold).
Most popular gold grades:
24 ct - stamp 1000. 24ct, 24kt, 24K
Melting point: 1064 C Density: 19.32 g/cm3
(100%)
22 ct – stamp: 916, 22ct. 22 kt, 22K
Melting range: 964-1020 C Density:17,7-17.9 g/cm3
22 carat gold (contain 91.6% pure gold)
18 ct – stamp : 750, 18ct.18kt, 18K.
Melting range: 880-960 C Density: 15.15-15.9 g/cm3
18 carat gold (contain 75.0% pure gold)
14 ct - stamp 583 or 585, 14ct,14kt, 14K.
Melting range: 830-970 C Density: 12.9 to 14.6 g/cm3
14kt gold (contain 58.5% pure gold)
9 ct – stamp: 375, 9ct, 9kt, 9K.
Melting range: 850-900 C Density: 10.9 to 12.7 g/cm3
9kt gold (contain 37.5% pure gold)
White Gold:
White golds for jewellery were developed in the 1920's as a substitute for platinum.
There is 2 basic classes of white golds - the Nickel whites and the Palladium whites.
White gold jewellery is normally electroplated with rhodium which is tarnish resistant and imparts a good white colour
Nickel white gold:
Nickel alloying additions form hard and strong white golds up to 18 carat.
Palladium white gold: They are available in all caratages up to 21 carat. Additions of about 10 -12% palladium to gold impart a good white colour. But palladium is an expensive metal, dearer than gold and it is also a heavy metal. Thus palladium white golds will be more expensive than identical pieces in nickel whites for 2 reasons: firstly, the cost of the palladium and secondly, the impact of density - palladium white golds are denser and so such jewellery will be heavier and also contain more gold. Many commercial palladium white golds only contain about 6-8% palladium plus silver, zinc and copper. Some may even contain some nickel, so a palladium white gold is not necessarily nickel-free.
Red or Rose-coloured gold: Rose-coloured gold is alloyed with copper and is often used to accent white or yellow gold.
Gold Grades hardness:
Choosing jewellery, particularly rings, many people consider the hardness and durability of gold to be used in their ring.
Metal hardness is measured by what is called the Vickers scale where harder metals receive a higher Vickers score than less hard metals.
9kt has a Vickers hardness of 120 and 18kt has a Vickers hardness of 125. This shows 18kt as harder, but the difference is so slight that in practical terms 9kt and 18kt are much the same in terms of hardness.
Another difference that should be considered when comparing 9kt and 18kt, 9kt is more difficult to bend and is a little more springy and therefore a fine 9kt ring may be less likely to bend out of shape than a fine 18kt ring. However, if the ring is of a good sturdy construction neither metal will be likely to bend out of shape.
Palladium:
Melting point: 1554.9 C Density: 12.023 g/cm3
Palladium is a rare transition metal with the symbol (Pd) from the traditional abbreviation for the Latin Argentum. Palladium was originally discovered within platinum ores, and is chemically similar to platinum. Palladium occurs within naturally alloyed gold or platinum, and as a 'free metal.'Like platinum, palladium has a lustrous silver-white colour and it is ideal for use in jewellery. As palladium jewellery is manufactured from 95 – 100% pure palladium, the jewellery is hypo-allergenic. This means that it is the ideal metal for people with sensitive or irritable skin.
Palladium is a very hard metal; in fact, it is 12% harder than platinum. It is also 40% lighter than platinum, a statistic that translates into a significant saving when it comes to purchasing palladium jewellery. Because palladium is a naturally white metal, there is no need to rhodium-plate it and palladium jewellery will keep it’s colour over time.
The price of palladium is fraction of platinum and gold price and when compared to an identically designed platinum or gold jewellery a palladium jewellery will weigh significantly less and will thus cost less.
Silver:
Melting point: 961.78 C Density: 10.49 g/cm3
Silver is a very ductile malleable (slightly harder than gold) with a brilliant white metallic luster that can take a high degree of polish. Among metals, pure silver has the highest thermal conductivity.
Silver jewellery and silverware are traditionally made from sterling silver (standard silver), an alloy of 92.5% silver with 7.5% copper. In the US, only an alloy consisting of at least 92.5% fine silver can be marketed as "silver" stamped 925.
Sterling silver jewellery is often plated with a thin coat of 0.999 fine silver or rhodium to give the item a shiny finish.
Pendant
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A pendant (from Old French) is a hanging jewellery object, generally attached to a necklace, chain or an earring.
Pendants can have several functions: Ornamentation, Identification, Protection (amulets), Self-affirmation, Ostentation, Award. |
Pavé
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The pavé setting, pronounced “pa-vay,” comes from the French word “to pave,” as in paved with stones.
By closely setting small stones together with minimal visibility of the tiny metal beads or prongs holding the stones in place, the effect is one of continuous sparkle. |
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Pavilion
The pavilion is the “bottom half” of the diamond. While the pavilion is usually hidden under a ring setting, it is an important part of a diamond’s overall look, as the pavilion contains facets that help light bounce, enter, and reflect through the diamond, giving it brilliance and fire.
Prong Setting
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This is a popular setting style and allows the maximum amount of light to shine through the stone. Prongs or claws are bent over and evenly spaced around the center stone. This setting allows for different stone shapes.
It can be Four Prong, Six Prong or Multiple Prong setting.. |
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R
Refractive Index
In optics, the refractive index or index of refraction of a material is a dimensionless number that describes how light propagates through that medium. It is defined as:
n=c/v
where c is the speed of light in vacuum and v is the phase velocity of light in the medium.
For example, the refractive index of water is 1.333, meaning that light travels 1.333 times faster in vacuum than in the water.
Window glass 1.52
Polycarbonate 1.58
Flint glass 1.62
Sapphire 1.77
Cubic zirconia 2.15
Diamond 2.42
Moissanite 2.65
n=c/v
where c is the speed of light in vacuum and v is the phase velocity of light in the medium.
For example, the refractive index of water is 1.333, meaning that light travels 1.333 times faster in vacuum than in the water.
Window glass 1.52
Polycarbonate 1.58
Flint glass 1.62
Sapphire 1.77
Cubic zirconia 2.15
Diamond 2.42
Moissanite 2.65
Relief
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A relief is a sculptured artwork where a carved or modeled form is raised (or in the case of a sunken relief, lowered) from a plane from which the main elements of the composition project (or sink).
The term relief is from the Latin verb “levo”, to raise. Raising or lowering the plane is achieved by removing material not relevant to the image. In the case of sunken relief, the material composing the central image is carved out. |
Rhodium-plating
Rhodium plating is a metal deposition process used to coat materials with a decorative and protective layer of rhodium for white gold jewellery, silver jewellery and stainless steel jewelry.
Rhodium is a precious metal – like gold, silver, or platinum.
Rhodium was discovered in 1803 by William Hyde Wollaston, who isolated it from platinum. He named it after the Latin rhodon, meaning rose. Wallaston was also the discoverer of palladium.
It is often used to hide imperfections and lend a higher sheen to silver or white gold pieces. Being harder than both silver and gold, it also makes an excellent protective coat that shields jewelry from scratches.
Rhodium plating is also a good recommendation for customers who are allergic to silver or nickel, as it will protect them from direct contact.
Through normal use, this layer eventually comes off, making replating a necessity every few years.
The most frequently used method of applying rhodium finishes is the electroplating process.
Rhodium is a precious metal – like gold, silver, or platinum.
Rhodium was discovered in 1803 by William Hyde Wollaston, who isolated it from platinum. He named it after the Latin rhodon, meaning rose. Wallaston was also the discoverer of palladium.
It is often used to hide imperfections and lend a higher sheen to silver or white gold pieces. Being harder than both silver and gold, it also makes an excellent protective coat that shields jewelry from scratches.
Rhodium plating is also a good recommendation for customers who are allergic to silver or nickel, as it will protect them from direct contact.
Through normal use, this layer eventually comes off, making replating a necessity every few years.
The most frequently used method of applying rhodium finishes is the electroplating process.
Ring and ring finger
The ring finger is the fourth digit of the human hand and the second most ulnar finger, located between the middle finger and the little finger.
A finger ring is a circular band worn as a type of ornamental jewellery around a finger; it is the most common current meaning of the word ring.
Other types of metal bands worn as ornaments are also called rings, such as arm rings or neck rings.
Gold and silver jewellery rings ( or made from other metal or materials) are worn by both men and women and can be of any quality. Rings can be made of precious metals, metal, plastics, wood, bone glass, gemstone and other materials. The ring may plane or be set with a "stone" of some sort, which is often a precious stone or semi-precious gemstone .
The custom of giving and receiving rings dates back over 4,80
A finger ring is a circular band worn as a type of ornamental jewellery around a finger; it is the most common current meaning of the word ring.
Other types of metal bands worn as ornaments are also called rings, such as arm rings or neck rings.
Gold and silver jewellery rings ( or made from other metal or materials) are worn by both men and women and can be of any quality. Rings can be made of precious metals, metal, plastics, wood, bone glass, gemstone and other materials. The ring may plane or be set with a "stone" of some sort, which is often a precious stone or semi-precious gemstone .
The custom of giving and receiving rings dates back over 4,80
Ring Sizes
S
Stone setting type
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Prong Setting
This is a popular setting style and allows the maximum amount of light to shine through the stone. Prongs or claws are bent over and evenly spaced around the center stone. This setting allows for different stone shapes. It can be Four Prong, Six Prong or Multiple Prong setting. |
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Bezel Setting
Full Bezel - The center stone is set deep and is fully encircled by metal. Thus, this offers maximum protection to the stone. A full bezel can accommodate any gemstone shape and is used in many kinds of jewelry. Semi-Bezel - The semi-bezel shows off more of the diamond, while still protecting it. Light can enter through more angles than in the full bezel setting. |
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Flush / Gypsy Setting
The difference between a bezel setting and gypsy setting is that the metal on a bezel setting will almost seem to come up over the gemstone, whereas in a gypsy setting the gemstone is sunk into the metal, so the gemstone sits below the surface of the metal. A gypsy setting is also known as a flush setting. |
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PAVÉ Setting The pavé setting, pronounced “pa-vay,” comes from the French word “to pave,” as in paved with stones. By closely setting small stones together with minimal visibility of the tiny metal beads or prongs holding the stones in place, the effect is one of continuous sparkle. |
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Channel setting
A channel setting is a type of mounting in which gemstones are set into a channel made from two metal strips. |
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V
Vickers scale
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The Vickers hardness test was developed in 1924 by Smith and Sandland at Vickers Ltd as an alternative to the Brinell method to measure the hardness of materials.
The Vickers test is often easier to use than other hardness tests since the required calculations are independent of the size of the indenter, and the indenter can be used for all materials irrespective of hardness. The basic principle, as with all common measures of hardness, is to observe the questioned material's ability to resist plastic deformation from a standard source. In the metallurgical world hardness is now usually expressed by means of the Vickers's hardness numbers or their equivalent. |
The Vickers test can be used for all metals, ceramics, composites (almost any type of material) and has one of the widest scales among hardness tests.
A square base pyramid shaped diamond is used for testing in the Vickers scale. Typically loads are very light, ranging from a few grams to one or several kilograms, although "Macro" Vickers loads can range up to 30 kg or more.
A square base pyramid shaped diamond is used for testing in the Vickers scale. Typically loads are very light, ranging from a few grams to one or several kilograms, although "Macro" Vickers loads can range up to 30 kg or more.
W
Wedding ring
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A wedding ring or wedding band is a metal or precious metal gold or silver jewellery ring indicating the wearer is married. Depending on the local culture, it is worn on the base of the right or the left ring finger. The custom of wearing such a ring has spread widely beyond its origin in Europe. Originally worn by wives only, wedding rings became customary for both husbands and wives during the 20th century. Unlike other jewellery the wedding ring is worn day and night and rarely removed.
The fourth digit or ring finger of the hand has become the customary place to wear a wedding ring in much of the world. It stems from a 16th-century Tudor belief (Tudor dynasty or House of Tudor ruled the Kingdom of England and Kingdom of Ireland, from 1485 until 1603. Its first monarch was Henry Tudor.) that the left-handed ring finger was connected by a vein directly to the heart; thus, wearing a ring on the third finger demonstrated that the wearer was in a relationship. |
