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Topaz Properties |
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Composition |
Al2(F,OH)2SiO4 |
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Refractive Index |
1.609-1.643 |
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Hardness: |
8 Mohs |
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Specific Gravity: |
3.49-3.57 |
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Typical Cutting Style: |
faceted |
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Optic Character: |
DR, biaxial positive |
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Polish Luster: |
Vitreous |
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Cause of Color: |
Chromium |
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Cleavage: |
Perfect in one direction |
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Typical Size Range: |
5 to 25 ct; faceted stones over
2000 ct have been cut for museums |
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Public Recognition: |
Well Known |
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Birefringence: |
0.008 to 0.010 |
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Dispersion: . |
.014 |
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Pleochroism: |
Yellow: definite; lemon-honey, straw-yellow |
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Fracture: |
Conchoidal, uneven |
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