Black Onyx

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CHEMISTRY SiO₂
CRYSTALLOGRAPHY Hexagonal, microcrystaline.
REFRACTIVE INDEX 1.544 - 1.553
HARDNESS 7
SPECIFIC GRAVITY 2.651
CLEAVAGE None
HEAT SENSITIVE No

WEARABILITY* Excellent
SPECIAL CARE INSTRUCTIONS None

ENHANCEMENTS Dying, common

*Wearability is graded as Excellent, Very Good, Good, Poor, and Forget It!
For more details see the article on "Hardness and Wearability."

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