Sunday, August 21, 2005

Opal

August 21, 2005
Opal

Opal A transparent to nearly opaque mineral or mineraloid (SiO 2 . nH 2 O) consisting of packed spheres of silica and [...]

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Zirconia

August 21, 2005
Zirconia

Zirconia The oxide of zirconium, obtained as a white powder, and possessing both acid and basic properties. On account of its infusibility, [...]

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Aventurine

August 21, 2005
Aventurine

Aventurine A quartzite gemstone, usually green with mica inclusions. Blue aventurine is found in India near cobalt deposits. ART Precious & Collectible [...]

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Agate

August 21, 2005
Agate

Agate chalecedony quartz that forms in concentric layers in a wide variety of colors and textures. Each individual agate forms by filling [...]

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