Glittering Stones >>Semi Precious Stones >> Topaz

Semi Precious Stone Topaz

Topaz is very common gemstone that has been used few centuries in jewelry. Its golden brown to yellow color is classic but it is confused with the less valuable citrine that is sold under the name topaz. The blue topaz that is often confused with aquamarine is not often natural and is produced by irradiating and then heating clear crystals. Topaz is the November Birthstone.

The mineral topaz is a silicate of aluminum and also fluorine with the chemical formula (AlF) 2SiO4. It is orthorhombic and its crystals are mainly prismatic terminated by pyramidal and other faces also, the basal pinacoid often being present. It has an easy and perfect basal cleavage and hence gemstones and other fine specimens must be handled with care to avoid developing cleavage flaws. The fracture is concordat to uneven. Topaz has a hardness of 7, a specific gravity of 3.4-3.5, and a vitreous luster. Pure topaz is transparent but it is usually tinted by impurities; typical topaz is wine and straw-yellow. They can also be white, gray, green, blue, or reddish-yellow also and transparent or translucent. When heated, yellow topaz often becomes reddish-pink.

Historical Facts of Topaz

Refractive Index: 1.629 - 1.637

Chemical Composition: AL(F,OH)2SIO4

Hardness: 8

Crystal Group: Orthorhombic

Density: 3.52 - 3.56

Color: Colorless, Blue, Yellow brown, Pinkish Orange, Red Orange, Red Brown, Tan, White, Gray, Green, Pink, Reddish Yellow.

Ocurrence: Brazil, Sri Lanka, Nigeria, Germany, Australia, Japan, Russia, Ireland, Zimbabwe, Western Utah, United States

Gemstone Jewelry Topaz