16.37: Obsidian

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    From LibreTexts, under CC BY-NC-SA 2.5, as the source states it; its equations are written in TeX, which the PDF shows typeset. This page at LibreTexts.

    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

    • Snowflake 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, Italy, Iceland, Indonesia, and Equador.

    This page titled 16.37: Obsidian was last modified on Fri, 06 May 2022 23:29:22 GMT and is shared under a CC BY-NC-SA 2.5 license and was authored, remixed, and/or curated by gemology via source content that was edited to the style and standards of the LibreTexts platform.