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 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 to dark brown in color with a vitreous luster and conchoidal fracture.
Formation & geological history
Formed from rapidly cooling felsic lava extruded from a volcano, preventing crystal growth.
Uses & applications
Historically used for making sharp cutting tools, arrowheads, and blades, and currently used in jewelry and decorative objects.
Geological facts
Despite its glass-like appearance, obsidian is a naturally occurring mineraloid rather than a true mineral because it lacks a crystalline structure.
Field identification & locations
Identified easily by its shiny, dark appearance and sharp conchoidal fracture edges; found globally in areas with active or recent volcanic history.
