igneous
Obsidian
Volcanic Glass
AI-generated identification · may be incorrectHardness of 5 to 5.5 on the Mohs scale, deep black color with vitreous luster, amorphous crystal structure with conchoidal fracture.
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Physical properties
Hardness of 5 to 5.5 on the Mohs scale, deep black color with vitreous luster, amorphous crystal structure with conchoidal fracture.
Formation & geological history
Formed by the rapid cooling of viscous lava rich in silica, without sufficient time for crystal growth.
Uses & applications
Used historically for cutting tools and arrowheads, and presently for ornamental carvings, jewelry, and surgical blades.
Geological facts
Obsidian is naturally occurring volcanic glass and lacks a true crystalline lattice, classifying it as a mineraloid.
Field identification & locations
Easily identified by its glass-like appearance, conchoidal fracture, and sharp edges. Found near recent volcanic activity worldwide.
