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Reference Values of Gems
Database updated: 15 Jan 2017
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Amethyst

  • Color: violet, purple-violet
  • Hardness: 7
  • Refractive index: 1.54 - 1.55
  • Density: 2.65 - 2.66
  • Chemical composition: SiO2
  • Crystal structure: hexagonal
  • Lustre: vitreous
  • Origins: Widespread; main sources are Brazil, Uruguay, Bolivia, Argentina, USA, East Africa, Zambia, Namibia, Madagascar, India, Sri Lanka, Russia, Australia.

Amethyst is a transparent purple-violet variety of quartz. The best amethysts have a medium dark violet color and uniform coloring. They are rarely heated to lighten dark colors or to improve transparency. An amethyst will change color to yellow or greenish yellow after heat treatment. Long time exposure to direct sunlight may make the color fade.

 

Amethyst 39.00 cts. Amethyst 20.20 cts.
Amethyst 39.00 cts.
Published under permission: Miguel Angel Lopez
Amethyst 20.20 cts.
Published under permission: Miguel Angel Lopez
Amethyst 26.54 cts. Amethyst Prasiolite 3.01 cts.
Amethyst 26.54 cts.
Published under permission: Miguel Angel Lopez
Amethyst Prasiolite 3.01 cts.
Published under permission: Miguel Angel Lopez

 


Market values of Amethyst  

Occurrence of Amethyst  

Historical values  


 
 
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