igneous
Obsidian
Volcanic glass
AI-generated identification · may be incorrectMohs hardness of 5 to 5.5, black or dark brown color, vitreous luster, amorphous crystal structure with conchoidal fracture.
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Physical properties
Mohs hardness of 5 to 5.5, black or dark brown color, vitreous luster, amorphous crystal structure with conchoidal fracture.
Formation & geological history
Formed from rapidly cooled felsic lava extruded from volcanic vents, lacking time for crystal growth.
Uses & applications
Used historically for cutting tools and arrowheads, and currently utilized in ornamental jewelry and surgical scalpel blades.
Geological facts
Despite its dark appearance, obsidian is chemically rich in silica and resembles synthetic glass.
Field identification & locations
Identified by its sharp conchoidal fracture and glossy vitreous luster, commonly found in regions with recent volcanic activity.
