igneous
Obsidian
Volcanic glass
AI-generated identification · may be incorrectHardness 5 to 5.5 on Mohs scale, black or dark brown color, vitreous luster, amorphous crystal structure with conchoidal fracture.
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Physical properties
Hardness 5 to 5.5 on Mohs scale, black or dark brown color, vitreous luster, amorphous crystal structure with conchoidal fracture.
Formation & geological history
Formed by the rapid cooling of felsic lava extruded from a volcano, preventing crystal growth.
Uses & applications
Historically used for cutting tools and weapons; today utilized in surgical scalpel blades and jewelry.
Geological facts
Despite appearing as a mineral, it is actually a mineraloid because it lacks a crystalline structure.
Field identification & locations
Identified by its glass-like appearance, dark color, and sharp conchoidal edges. Found worldwide in areas with recent volcanic activity.
