igneous
Obsidian
Volcanic glass
AI-generated identification · may be incorrectHardness of 5 to 5.5 on the Mohs scale, typically black or dark brown in color with a vitreous luster and conchoidal fracture.
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Physical properties
Hardness of 5 to 5.5 on the Mohs scale, typically black or dark brown in color with a vitreous luster and conchoidal fracture.
Formation & geological history
Formed through the rapid cooling of viscous lava rich in silica, without crystal growth, typically from rhyolitic flows.
Uses & applications
Historically used for cutting tools, arrowheads, and blades; currently valued in lapidary arts, jewelry, and ornamental carving.
Geological facts
Obsidian lacks a true crystalline structure, classifying it as a mineraloid rather than a mineral.
Field identification & locations
Easily identified by its glass-like appearance and extremely sharp conchoidal fracture edges; found globally in areas with recent volcanic activity.
