igneous
Obsidian
Volcanic glass
AI-generated identification · may be incorrectHardness 5-5.5 on Mohs scale, black or dark brown color, vitreous luster, amorphous crystal structure with conchoidal fracture.
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Physical properties
Hardness 5-5.5 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 viscous felsic lava from volcanic eruptions, preventing crystal growth.
Uses & applications
Historically used for making sharp cutting tools, arrowheads, and blades; currently used in jewelry and decorative objects.
Geological facts
Despite looking like a mineral, obsidian is actually a mineraloid because it lacks a crystalline structure.
Field identification & locations
Identified by its glass-like appearance and sharp conchoidal fracture edges; found globally in areas with recent volcanic activity.
