obsidian

1. n. A kind of glass produced by volcanoes. It is usually of a black color, and opaque, except in thin splinters. Source: opted

2. n. acid or granitic glass formed by the rapid cooling of lava without crystallization; usually dark, but transparent in thin pieces Source: wordnet

3. A kind of glass produced by volcanoes. It is usually of a black color, and opaque, except in thin splinters. Note: In a thin section it often exhibits a fluidal structure, marked by the arrangement of microlites in the lines of the flow of the molten mass. Source: webster

4. A kind of glass produced by volcanoes. It is usually of a blackcolor, and opaque, except in thin splinters. Source: adambom

5. n:100 n. acid or granitic glass formed by the rapid cooling of lava without crystallization; usually dark, but transparent in thin pieces Source: ecdict

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