igneous
Obsidian
Volcanic Glass
AI-generated identification · may be incorrectHardness 5-5.5 on Mohs scale, typically black to dark brown, vitreous luster, amorphous crystal structure with conchoidal fracture.
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Physical properties
Hardness 5-5.5 on Mohs scale, typically black to dark brown, vitreous luster, amorphous crystal structure with conchoidal fracture.
Formation & geological history
Formed as extrusive igneous rock when felsic lava cools rapidly with minimal crystal growth.
Uses & applications
Historically used for sharp tools and weapons like arrowheads; currently utilized in decorative jewelry and surgical scalpel blades.
Geological facts
Despite its glass-like appearance, obsidian is a naturally occurring mineraloid rather than a true mineral.
Field identification & locations
Identify by its distinctive conchoidal fracture and sharp glass-like edges; found worldwide in areas of recent volcanic activity.
