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Zircon:
Neosilicates (Zirconium silicate, often with some hafnium) ZrSiO4 AKA: Cubic Zirconia or "CZ" |
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System: Tetragonal; generally in simple short primatic crystals showing square cross section terminated by the pyramid; also irregular lumps, disseminated grains. Appearance: Gray, brown, yellow, green, red transparent (hyacinth), colorless, or smoky (jargoon); adamantine, vitreous; streak colorless. Physical Properties: Hardness: (7.5); Specific gravity: (4.6 -4.7). Cleavage: indistinct, two directions parallel to prism faces; fracture, uneven; transparent to translucent; fluorescent; brittle. Similar species: Vesuvianite. Zircon has a higher specific gravity than vesuvianite. Occurrence: Zircon develops in igneous and metamorphic rocks, and is common accessory mineral in the common types of plutonic rocks. Although they do not form in placer deposits, these deposits are the commercial source for gem and industrial zircon. Large brown crystals have been found in Ontario; black crystals from New Jersey and Colorado; and well-formed, double terminated crystals from Oklahoma. In general, good specimens come from North America, but gem-quality material comes from foreign sources, particularly Ceylon, Burma and France. Miscellaneous: Transparent gem-quality zircon is produced by heat-treating natural zircon. Colorless or pale gray zircon is called jargoon, and yellow, orange and red zircons are called hyacinth. Other gem varieties are blue, green, violet and brown zircon. Colors produced by heat-treating are likely to fade upon prolonged exposure to sunlight. Blue zircon is said to be the most popular and valuable. All stones are faceted. The name is from the Persian zargun, "gold-colored". Zircon is a source of zirconium and hafnium. Zircon is a December birthstone. Conventional Wisdom: All colors. Clear, colorless, natural form: This mineral promotes unions: physical, mental, emotional, spiritual, etc. It acts to increase ones hardiness and to facilitate community in all endeavors. Zircon also symbolizes innocence, purity and consistency. Man-made (cubic Zirconia or "CZ") is not nearly as strong/effective as the natural form. Belongs to the Astrological Signs of Virgo, Leo and Sagittarius. |