igneous
Obsidian
Volcanic Glass
AI-generated identification · may be incorrectHardness of 5 to 5.5 on the Mohs scale, black or dark brown color, vitreous luster, and conchoidal fracture.
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Physical properties
Hardness of 5 to 5.5 on the Mohs scale, black or dark brown color, vitreous luster, and conchoidal fracture.
Formation & geological history
Formed as extrusive igneous rock when felsic lava cools rapidly with minimal crystal growth.
Uses & applications
Used historically for sharp tools and weapons, and currently for ornamental carvings and jewelry.
Geological facts
Despite its glass-like appearance, it is a naturally occurring rock rather than a man-made substance.
Field identification & locations
Identified by its shiny, smooth texture and sharp conchoidal edges, commonly found near recent volcanic activity.
