Obsidian

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Obsidian (named after the roman, Obsius) is a volcanic glass.

Diagnostics

Color

Its color is black, grey, brown, green and can be gold or silver due to inclusions

Diaphaneity

Transparent to opaque

Hardness

Obsidian has a hardness of 5-5 1/2

Specific gravity

Obsidian has a density of 2.35-2.60

Refractive index

Obsidian is singly refractive with an R.I. range of 1.45 to 1.55

Varieties

  • Snow flake obsidian is the trade name for an obsidian with grey-white, ball shaped inclusions of Spherulites found in Mexico and the United States

Localities

Deposits are found in the United States, Mexico, Japan, Itally, Iceland, Indonesia and Equador.