igneous
Obsidian
Volcanic Glass
AI-generated identification · may be incorrectHardness 5.5 on Mohs scale, black or dark brown color, vitreous luster, amorphous crystal structure with conchoidal fracture.
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Physical properties
Hardness 5.5 on Mohs scale, black or dark brown color, vitreous luster, amorphous crystal structure with conchoidal fracture.
Formation & geological history
Formed by the rapid cooling of viscous felsic lava from volcanic eruptions, lacking time for crystal growth.
Uses & applications
Historically used for cutting tools and weapons like arrowheads, and currently utilized in surgical scalpel blades and jewelry.
Geological facts
Because it contains no crystal structure, obsidian breaks with extremely sharp edges that can be sharper than high-quality steel.
Field identification & locations
Easily identified by its glassy appearance, dark color, and characteristic curved conchoidal fracture patterns. Found globally in areas with recent volcanic activity.
