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Reference Values of Gems
Database updated: 15 Jan 2017
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Tanzanite


  • Color: blue, violet blue, green, yellow, brownish
  • Hardness: 6,5 - 7
  • Refractive index: 1.69 - 1.70
  • Density: 3.35 - 3.38
  • Chemical composition: Ca2Al3(O/OH/SiO4/Si2O7)
  • Crystal structure: orthorhombic
  • Origins: Tanzania

The most valued tanzanites (zoisites) are typically vivid, violet-blue crystals with greenish or orangey stones being rare. Heat treatment is applied to enforce the violet color component.

 

Tanzanite 2.34 cts.
Tanzanite 2.34 cts.
Published under permission: Miguel Angel Lopez

 


Market values of Tanzanite  

Occurrence of Tanzanite  

Historical values  


 
 
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