Difference between revisions of "Topaz"

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==Synthetics==
 
==Synthetics==
  
Although topaz is synthezised, the material is not commercially available.
+
Although topaz is synthesized, the material is not commercially available.
  
 
==Sources==
 
==Sources==
  
 
* [http://www.gia.edu/newsroom/issue/2798/2696/insider_newsletter_details.cfm#2 From Gems & Gemology: A New Imitation of Imperial Topaz]
 
* [http://www.gia.edu/newsroom/issue/2798/2696/insider_newsletter_details.cfm#2 From Gems & Gemology: A New Imitation of Imperial Topaz]

Revision as of 05:02, 30 June 2007

Topaz
Chemical composition Al2(F,OH)2SiO4
Crystal system Orthorhombic
Habit Prismatic with pyramidal/domed terminations
Cleavage Perfect, basal plane
Fracture Sub-conchoidal to uneven
Hardness 8
Optic nature Biaxial +
Refractive index 1.606-1.644
Birefringence 0.008 - 0.010
Dispersion Low, 0.014
Specific gravity 3.49 - 3.57
Lustre Vitreous
Pleochroism Distinct to strong (depending on body color)
Peach Pink Imperial Topaz
Photo courtesy of Lembeck Gems

Red Imperial Topaz
Photo courtesy of Lembeck Gems

Imitations

Recently,2007, yellow-orange-pink flame-fusion corundum is offered in Minas Gerais, Brazil as imperial topaz.

Synthetics

Although topaz is synthesized, the material is not commercially available.

Sources