Jade has been called the stone of the heavens, the musical stone, the stone of the loins and
some people believe it can predict the future. Found in mountains and riverbeds it is
considered to be the essence of Heaven and Earth.
Jade refers to two similar types of stones that are chemically different: jadeite,
a silicate of sodium and aluminum, and nephrite, a silicate of calcium and magnesium.
Although different, they share many common characteristics. In Europe, the technical
characteristics of the two varieties were first published by Damour in 1863; the Chinese
were aware of the differences long before.
Over the centuries the name Jade has been incorrectly applied to a wide variety of
minerals including: Serpentine, Turquoise, Malachite, Agate, Hornblende, Marble, Amazonite
(Green Feldspar), Idocrase, Calcite, Aventurine, Amethyst, Coral, Ruby and Sapphire.
Coloration
Pure Jade is pure white. All other colors are due to minute quantities of metals such as
iron, chromium, vanadium and magnesium in the crystalline structure. The most sought after
color is a deep translucent green known as Imperial Jade. Other popular colors include
Lavender Jade, Blue Jade, Purple Jade and even Jade Cats Eyes. White Jade is traditionally
known as Mutton Fat Jade.
Hardness
Although it measures just 6-7 on the Moh’s Scale of Hardness, Jade is actually very tough.
It is this toughness that has ensured its enduring popularity and makes it an ideal gem for
jewelry. Jade carvings, cameos and pendants are timeless and bracelets, necklaces and chokers
made from Jade Beads (including various fancy colors) are another versitile favorite.
Sources
Jade is found in a variety of locations with Myanmar, Guatemala and Russia’s Ural Mountains
the main commercial deposits. Other Jade locations include: Rhotan in Mountainous Western
China, The Jordensmishl Nephrite Jade Deposit in Poland, the Appenine Mountains in Italy,
India, Switzerland and the Netherlands.
The highest quality comes from Siberia, and sometimes New Zealand or Australia. Taiwan has
good nephrite, but the largest producer by far is British Columbia.
Evaluating Fine Jade
When evaluating Jade there are four main factors to consider:
Color: The color should be penetrating, vivid and also be evenly distributed.
Translucency: The clarity should be as consistent as honey while the translucency
can range from near transparent to opaque.
Texture: Jade can be fine or coarse but the best quality is clear and free of impurities.
Cutting: As Jade is often sold as finished artworks, the quality of the workmanship is
critically important.
Technical Characteristics
Jadeite
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Chemical Composition:
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NaAlSi2O6 - Silicate of Sodium and Aluminum
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Hardness:
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6.5 - 7.0
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Specific Gravity:
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3.3-3.8
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Refractive Index (R.I.):
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1.65 - 1.68
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Texture:
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Interlocking Granular Structure
(microcrystalline)
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Surface Luster:
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Vitreous, sometimes Greasy
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Fracture Structure:
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Granular, possibly Splintery
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Nephrite
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Chemical Composition:
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Silicate of Calcium and Magnesium
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Hardness:
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6.0 - 6.5
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Specific Gravity:
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2.9-3.0
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Refractive Index (R.I.):
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1.60 - 1.63
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Texture:
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Interwoven Fibrous Structure
(Cryptocrystalline)
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Surface Luster:
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Greasy, sometimes Vitreous
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Fracture Structure:
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Splintery, possibly Granular
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