Name:
Topaz
Chem:
Al2(SiO4)(F,OH)2
Hydroxy-fluoro-aluminum silicate
Crystal:
Orthorhombic (prisms with multifaceted ends common)
Color:
clear, blue, pink, orange-red, red-brown
Refrac. Index:
1.61 - 1.638
Birefraction:
0.014
Hardness:
8
Spec. Grav.:
3.53 - 3.56
Fracture:
conchoidal
Cleavage:
perfect
Environment:
It is a high temperature mineral usually found in igneous rocks and high temperature veins. Also in hydrothermal replacement deposits.
Association:
beryl, quartz, rutile, orthoclase, albite
Locals:
| Brazil | USSR | Utah, Calif., Co, N.H., USA | Sri Lanka | Mexico |
Misc:
The name Topaz is thought to be derived from the name Topazion, the old name for the island of Zebergit (St. Thomas Island) in the Red Sea. The Sanskrit word "Tapas" means "fire". It is insoluble in acids. Some varieties are heat sensitive.
Gem info:
Clear topaz has little value, and is quite prevalent. Some varieties can be irradiated to various shades of blue, and this acceptable in the trade. Most blue topaz on the market today is irradiated. There is a grayish variety of topaz that is sometimes cut to produce a stone called "champaign" topaz.
Blue topaz is rare in nature, but easily created from clear material. There is an abundance on the world market, and very large, flawless stones are easily available. It is relatively low in value, about the same as good amethyst.. It is available in shades of blue from very light, through sky-blue, and on to almost an inky blue. Overtones of gray are not desirable, and further reduce its value.
Red-brown topaz is also common and found in Mexico and Utah, it makes a nice faceted stone, and some don't. It is sometimes called "rootbeer" topaz. Again it is not of high value. It is typically more expensive than citrene, and far less than morganite, or good golden beryl.
Imperial-topaz is the most prized, and is a red-orange to a pink-orange color. The color is due to the presence of hydroxyl ions, and hence this variety is heat sensitive, and it usually contains numerous flaws. Preferred colors make this stone about the same in value as good aquamarine.
Pink topaz is fairly rare, but highly valued. Green is another rare color, but highly valued. Although pink is occasionally found in jewelry, the green is very rarely found.
Many times smoky quartz (under the name "smoky topaz"), or citrene (under the name "Bahia or Maderia topaz") is sold as a variety of topaz to increase the value of the quartz. Buyer beware!
clear teardrop w/rutile
clear tear w/rutile (closeup)
clear rectangle w/rutile
clear cutrect w/rutile (closeup)
clear cutrect w/rutile (closeup2)
blue carved
