igneous
Obsidian
Volcanic glass
AI-generated identification · may be incorrectHardness of 5 to 5.5 on the Mohs scale, typically black to dark brown in color, vitreous luster, conchoidal fracture, and amorphous crystal structure.
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Physical properties
Hardness of 5 to 5.5 on the Mohs scale, typically black to dark brown in color, vitreous luster, conchoidal fracture, and amorphous crystal structure.
Formation & geological history
Formed from rapidly cooling felsic lava extruded from a volcano, preventing crystal growth.
Uses & applications
Used historically for cutting tools and arrowheads, and currently in decorative objects and surgical scalpel blades.
Geological facts
Obsidian fractures with extremely sharp edges, often forming thinner edges than high-quality steel.
Field identification & locations
Identify by its glassy luster, dark color, and characteristic conchoidal fracture patterns; found globally in areas with recent volcanic activity.
