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Deposits of
Onyx are excavated in different countries including Brazil,
Madagascar, Algeria, India and Pakistan. Onyx is mostly seen in
black color though it is available also in various other shades,
such as red, yellow, green, blue, white and reddish brown. Due
to its affordness it is used widely in
the Jewellery manufacturing. On the Mohs
scale, it has a hardness of 6.5 to 7.
Onyx (SiO2 with impurities) is a member of the Quartz family. Color
Onyx is usually black, ray or brown with white bands.
Specific Gravity 2.65
Refractive Index 1.55 - 1.54
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