hydroxy-fluoro-aluminum silicate


Topaz is a silicate mineral that has been valued for centuries as a gemstone used in jewelry. Mineralogists call topaz a hydroxy-fluoro-aluminum silicate, with the chemical formula Al2SiO4(F,OH)2.

Topaz is the hardest silicate mineral, but it can be split with a single blow, a trait it shares with diamonds. The crystals can reach an enormous size of several hundred pounds. Topaz make very attractive mineral specimens due to its high luster, lovely colors and well-formed, multi-faceted crystals. But most so-called topazes are really citrines, a Brazilian yellow quartz, produced by heating smoky quartz .

The name topaz may come from the old Sanskrit word "tapaz," which means fire, based on a common misconception that all topaz is golden in color. Pure topaz is colorless, but it occurs in a variety of colors due to various impurities -- yellow, brown, orange, beige, red and green. Some rare and exceptional topaz is pale pink, sherry red or blue. Most blue topaz, however, is artificially created by the irradiation of pale topaz from Brazil, Sri Lanka, Nigeria or China.

In ancient folklore, topaz was believed improve the eyesight of the wearer and to dispel enchantments. Topaz was also said to change color in the presence of poisoned food or drink, which made it popular among early monarchs. It was believed that its mystical curative powers waxed and waned with the phases of the moon. Topaz was also said to cure insomnia and asthma as well as stop hemorrhaging.

The Egyptians believed topaz was colored with the golden glow of the sun god Ra, making it a powerful amulet to protect against harm. The Romans associated topaz with Jupiter, also the god of the sun in the Roman pantheon. The ancient Greeks said it had the power to increase strength and make its wearer invisible in times of emergency. Some experts today maintain that the topaz of modern mineralogists was unknown to the ancients, and that the stone called "topazos" was probably either chrysolite or peridot.

In the American Southwest, topaz is found in San Diego County, California, the Thomas Mountain Range of Utah, Pikes Peak, Colorado, and the Llano Uplift region of Texas. A famous blue topaz hunting ground is located in the Hill Country of Mason County, Texas, where North America's largest known gem-quality topaz was discovered in 1904. This 1,296-gram, pale-blue crystal now resides in the Smithsonian Institution in Washington DC.

Blue topaz was designated the Texas state gem in 1969. Topaz is the birthstone for November while blue topaz is the birthstone for December.


Crystal System
Al2 SiO4 (F,OH)3
8 (Mohs' scale)
Specific Gravity
Perfect in 1 direction, basal.
3.4 - 3.5+
Color, Transparency
& Luster
- Color clear, yellow, orange, red, blue & green
- Luster adamantine to vitreous.
- Streak white.
  • Limestone
  • Marble
  • Chalk
  • Travertine
  • Iceland Spar

-- Bob Katz



Related DesertUSA Pages



Share this page on Facebook:

DesertUSA Newsletter -- We send articles on hiking, camping and places to explore, as well as animals, wildflower reports, plant information and much more. Sign up below or read more about the DesertUSA newsletter here. (It's Free.)

The Desert Environment
The North American Deserts
Desert Geological Terms


Enter Email:

Shop desert store



life straw


Charger kit

Rockhound books

Hot temperatures in the desertAre you interested in the temperatures in the desert?

Click here to see current desert temperatures!

Copyright © 1996- and Digital West Media, Inc. - -