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Topaz
Current inventory:  0 gems
 

Chemistry:  Al₂SiO₄(F,OH)₃  [Aluminim Silicate Fluoride Hydroxide]

Discovered in Prehistory;   IMA status: Valid (pre-IMA; Grandfathered).
From the Greek topazion, meaning to seek, apparently in allusion to the Island of Zabargad (Zabirget or St. Johns), in the Red Sea, Egypt; the location of which was long hidden, known for Olivine ("Peridot" and "Chrysolite"), referred to as Topaz since antiquity.

Classification

Mineral Classification:

Silicates

Strunz 8th Ed. ID:

8/B.02-70

Nickel-Strunz 10th Ed. ID:

9.AF.35

9 : SILICATES (Germanates)
A : Nesosilicates
F : Nesosilicates with additional anions; cations in [4], [5] and/or only [6] coordination

Related to:

Disthene Series

Crystal Data

Crystallography:

Orthorhombic - Dipyramidal

Crystal Habit:

Well-formed crystals common, typically morphologically complex, long to short prismatic, to 1.2 m. Prism faces commonly vertically striated, with etch and growth figures on non-prism faces; columnar, compact, massive.

Twinning:

None

Physical Properties

Cleavage:

[001] Perfect

Fracture:

Subconchoidal to Uneven

Tenacity:

Brittle

Hardness (Mohs):

8.0

Density:

3.49 - 3.57 (g/cm³)

Luminescence:

Rarely; blue and colorless gems: weak yellow-green in LW UV, weaker in SW UV; sherry brown and pink gems: orange-yellow in LW UV, weaker in SW UV, sometimes greenish white in SW UV.

Radioactivity:

Not Radioactive

Optical Properties

Color:

Colourless, White, pale Blue, light Green, Yellow, Yellowish Brown, or Red

Transparency:

Transparent to Opaque with inclusions

Luster:

Vitreous

Refractive Index:

1.606 - 1.644  Biaxial ( + )

Birefringence:

0.0090 - 0.0110

Dispersion:

Noticable; 0.0140; r > v

Pleochroism:

Weak; X = yellow; Y = yellow, violet, reddish; Z = violet, bluish, yellow, pink

Occurances

Geological Setting:

In veins and cavities in granite, granite pegmatite, rhyolite, and in greisen, formed from high-temperature, volatile-rich pneumatolytic hydrothermal fluids. From high-grade metamorphism of aluminous, quartz-rich, and fluorine-bearing sediments. As a heavy detrital mineral.

Common Associations:

Albite, Beryl, Cassiterite, Fluorite, Microcline, Quartz, Tourmaline, Zinnwaldite

Type Locality:

n/a (Prehistoric)

Year Discovered:

Prehistoric

View mineral photos:

Topaz Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Topaz is an abundant and popular gem available in a wide variety of colors. Natural colors include colorless, pale to medium blue, pale greenish, yellow, golden brown, beige, champagne, orange, pale to deep pink and, rarely, red. Many other colors, including the popular deep blue, have been created by heating and irradiating Topaz. These colors have been given commercial names such as London Blue, Swiss Blue and Sky Blue. Treated Topaz is also available in shades of green from Teal Green to Emerald Green. Another Topaz treatment is to put a chemical coating on the surface of a faceted gem resulting in a rainbow of colors. This gem goes by the commercial name of Mystic Topaz.

Very large Topaz crystals have been found weighing hundreds of pounds. These crystals are often very gemmy and have produced faceted gems of up to 20,000 carats! Possibly the largest faceted gemstone in the world is a light blue Topaz (treated) from Brazil weighing 21,327 carats cut in an emerald shape called the Brazilian Princess. Many of the other colors of natural Topaz (yellow, orange, pink, red) are found as much smaller crystals. Natural orange Topaz is oftern called "Imperial" or "Precious" Topaz.

There are many locations worldwide where Topaz can be found. A few locations for the finest specimens include near Mursinka, Ural Mountains, Russia; the Skardu and Gilgit districts, Pakistan; the Mogok district, Myanmar (Burma); Ouro Preto, Minas Gerais, Brazil; Tepetate, San Luis Potosi, Mexico; and in the USA at Ramona, San Diego County, California; Devils Head, Douglas County, Colorado; the Thomas Range, Juab County, Utah, USA.
 

  
Topaz gems for sale:

We have not photographed our Topaz. Please check back soon.