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Topaz:
Neosilicates (Aluminum fluorsilicate) Al2SiO4(F,OH)2 AKA: |
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System: Orthorhombic; usually in stubby to medium-long prismatic crystals striated lengthwise; also granular, massive. Appearance: White, colorless, yellow, pink, bluish, greenish; vitreous; streak colorless. Physical Properties: Hardness: (8.0); Specific gravity: (3.4 - 3.6). Cleavage: perfect, one basal direction; fracture, subconchoidal, uneven; transparent to translucent. Similar species: Topaz is harder than quartz and has excellent cleavage, which is missing in quartz and beryl. Occurrence: Topaz is a high-temperature mineral and is generally found in igneous rocks and high-temperature veins. It occurs with beryl and quartz in granite pegmatites; with orthoclase and quartz in cavities in rhyolite of volcanic rocks; and with rutile and quartz in massive hydrothermal replacement deposits. The finest topaz is said to come from the former USSR, Sri Lanka and Brazil, but excellent specimens are also found in North America. Pale-blue and sherry-colored crystals have been found in cavities in granite rocks in New Hampshire and Colorado. Beautiful colorless and sherry-colored topaz occurs with fluorite, quartz, garnet and hematite in cavities in rhyolite in Utah and California. Miscellaneous: Gem-quality transparent topaz occurs in several colors, including colorless, pale greenish-yellow to yellowish-green, yellow to orange-yellow and blue. Dark orange to dark orange-red topaz is called hyacinth. The light red to light purplish-red topaz is produced by heat-treating sherry-colored or brownish-yellow stones. Flaws and inclusions are common in topaz, and clean fine stone are not common. Topaz stones are faceted. The name is from the Greek topazos, a name said to be applied to a gemstone whose identity has been lost. Conventional Wisdom: Topaz is know as the stone of true love and success in all endeavors. This mineral helps one to understand both the actions occurring in the "big picture" and the interrelationships occurring in the minute detail which comprises it. It promotes the expression of ideas and instills trust in the universe. The topaz crystal is considered quite precious by the African bushmen, being used in ceremonies for healing and for connecting with the spirits who have departed from this plane. It is considered to bring wealth and health to the holder. Belongs to the Astrological Sign of Sagittarius. |