igneous
Black Obsidian
Volcanic Glass
AI-generated identification · may be incorrectHardness 5 to 5.5 on the Mohs scale, jet black color, vitreous luster, amorphous crystal structure, conchoidal fracture, specific gravity around 2.4.
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Physical properties
Hardness 5 to 5.5 on the Mohs scale, jet black color, vitreous luster, amorphous crystal structure, conchoidal fracture, specific gravity around 2.4.
Formation & geological history
Formed from rapidly cooling felsic lava extruded from a volcano without sufficient time for crystal growth.
Uses & applications
Used historically for sharp cutting tools and arrowheads, and presently in jewelry, ornamental carvings, and holistic healing.
Geological facts
Despite appearing like a mineral, obsidian is technically a mineraloid because it lacks a crystalline structure.
Field identification & locations
Easily identified in the field by its glassy appearance and extremely sharp conchoidal fracture edges; found globally near recent volcanic activity.
