This page will contain wikis about Topaz, as they become available.

Topaz

This article is about the mineral or gemstone, for other uses see: Topaz (disambiguation).

Topaz 4 Carat Oval Shape Topaz Gemstone Ring Enhanced with Azotic(r)Treatment Heart Cut Sky Blue Topaz Ring

The mineral topaz is a silicate of aluminium and fluorine with the chemical formula Al2SiO4(F,OH)2. It crystallizes in the orthorhombic system and its crystals are mostly prismatic terminated by pyramidal and other faces, the basal pinacoid often being present. It has an easy and perfect basal cleavage and so gemstones or other fine specimens should be handled with care to avoid developing cleavage flaws. The fracture is conchoidal to uneven. Topaz has a hardness of 8, a specific gravity of 3.4-3.6, and a vitreous lustre. Pure topaz is transparent but is usually tinted by impurities; typical topaz is wine or straw-yellow. They may also be white, gray, green, blue, or reddish-yellow and transparent or translucent. When heated, yellow topaz often becomes reddish-pink. It can also be irradiated, turning the stone a light and distinctive shade of blue. A recent trend in jewelry is the manufacture of topaz specimens that display iridescent colors, by applying a thin layer of titanium oxide via physical vapor deposition.

Topaz is found associated with the more acid rocks of the granite and rhyolite type and may be found with fluorite and cassiterite. It can be found in the Ural and Ilmen mountains, Czech Republic, Saxony, Norway, Sweden, Japan, Brazil, Mexico, and the United States.

Etymology and historical/mythical usage

The name "topaz" is derived from the Greek topazos, "to seek," which was the name of an island in the Red Sea that was difficult to find and from which a yellow stone (now believed to be a yellowish olivine) was mined in ancient times. In the Middle Ages the name topaz was used to refer to any yellow gemstone, but now the name is only properly applied to the silicate described above.

According to Rebbenu Bachya, the word "Leshem" in the verse Exodus 28:19 means "Topaz" and was the stone on the Ephod representing the tribe of Dan.

Topaz is also the birthstone of November.

Example of Heat Treated Topaz-Pink Topaz Pear Cut Ring

References

  • Webmineral
  • Mindat with location data
  • Mineral galleries

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Topaz is also the birthstone of November. In particular, the auction website eBay has a policy stating that used garments must be completely clean before being listed for sale and listings for underwear are not allowed at all.[1]. According to Rebbenu Bachya, the word "Leshem" in the verse Exodus 28:19 means "Topaz" and was the stone on the Ephod representing the tribe of Dan. Used clothes are occasionally sold on the Internet. In the Middle Ages the name topaz was used to refer to any yellow gemstone, but now the name is only properly applied to the silicate described above. Used cars may require more maintenance or have fewer features than later equivalent models. The name "topaz" is derived from the Greek topazos, "to seek," which was the name of an island in the Red Sea that was difficult to find and from which a yellow stone (now believed to be a yellowish olivine) was mined in ancient times. George Akerlof published a paper entitled "The Market for Lemons", examining the effects of information asymmetry on the used car market.

It can be found in the Ural and Ilmen mountains, Czech Republic, Saxony, Norway, Sweden, Japan, Brazil, Mexico, and the United States. Used cars may have been bought or leased by their previous user, and may be purchased directly from the previous owner or through a dealer. Topaz is found associated with the more acid rocks of the granite and rhyolite type and may be found with fluorite and cassiterite. Used cars are especially notable for depreciating in value much faster than many other items. A recent trend in jewelry is the manufacture of topaz specimens that display iridescent colors, by applying a thin layer of titanium oxide via physical vapor deposition. Purchasing used items may also prevent them from becoming waste. It can also be irradiated, turning the stone a light and distinctive shade of blue. The strategy of buying used items is sometimes used to save money, as they are typically worth less than the equivalent new items.

When heated, yellow topaz often becomes reddish-pink. Some stores will take used items in exchange for credit toward the purchase of newer goods. They may also be white, gray, green, blue, or reddish-yellow and transparent or translucent. Used items can often be found for sale in thrift stores and pawnshops, as well as internet auction sites. Pure topaz is transparent but is usually tinted by impurities; typical topaz is wine or straw-yellow. When a person gives an item of some value that they have used to someone else, typically an acquaintance or family member, it is sometimes referred to as a "hand-me-down". Topaz has a hardness of 8, a specific gravity of 3.4-3.6, and a vitreous lustre. A used item is one that is not new or a resource that has been partially or completely depleted.

The fracture is conchoidal to uneven. . It has an easy and perfect basal cleavage and so gemstones or other fine specimens should be handled with care to avoid developing cleavage flaws. It crystallizes in the orthorhombic system and its crystals are mostly prismatic terminated by pyramidal and other faces, the basal pinacoid often being present. The mineral topaz is a silicate of aluminium and fluorine with the chemical formula Al2SiO4(F,OH)2.

This article is about the mineral or gemstone, for other uses see: Topaz (disambiguation).. Mineral galleries. Mindat with location data. Webmineral.

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