ametrine

Photo of an emerald cut, bicolor quartz known as ametrine, set in a custom 14K gold pendant. (Half amethyst, half citrine)
Photo courtesy of Scott Papper, GIA GG, AJP, Global Gemology & Appraisals
Variety:  Ametrine
Species:  Quartz
​​Mohs Hardness:  7 out of 10
Color:  Bicolor combination of purple and orange hues
RI:  1.544 to 1.553 (very constant)
Birefringence:  0.009
SR/DR/AGG:  DR
Optic Character:  Uniaxial positive.  Might show a bull's eye or Airy's spiral optic figure and Brazil law twinning under crossed polarizing filters.
Pleochroism:  Very weak.  Different tones of yellow and orange, different tones of purple and reddish purple
Spectrum:  Not diagnostic
Fluorescence:  Generally inert.
SG:  2.66 (+0.03 / -0.02)

ametrine facts

Photo of an emerald cut, bicolor quartz known as ametrine. (Half amethyst, half citrine)
Photo courtesy of Scott Papper, GIA GG, AJP, Global Gemology & Appraisals

Ametrine is a unique variety of quartz that displays both purple and orange hues of amethyst and citrine in the same gem!
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The Anahi mine in Bolivia is the world's only commercial source of ametrine.
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