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. It exhibits conchoidal fracture and an 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 with a vitreous luster. It exhibits conchoidal fracture and an amorphous crystal structure.
Formation & geological history
Formed from rapidly cooling felsic lava extruded from volcanic vents, preventing crystal growth.
Uses & applications
Historically used for cutting tools and weapons, and currently used in jewelry and decorative objects.
Geological facts
Despite its glass-like appearance, obsidian is a naturally occurring rock rather than a true mineral because it lacks a crystalline structure.
Field identification & locations
Easily identified by its sharp, curved edges and smooth, glossy black surface; commonly found in regions with recent volcanic activity.
