igneous
Obsidian
Volcanic glass
AI-generated identification · may be incorrectHardness 5-5.5, jet black color, vitreous luster, amorphous crystal structure with conchoidal fracture, specific gravity around 2.35.
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Physical properties
Hardness 5-5.5, jet black color, vitreous luster, amorphous crystal structure with conchoidal fracture, specific gravity around 2.35.
Formation & geological history
Formed through the rapid cooling of felsic lava rich in silica, preventing crystal growth; typically associated with rhyolitic volcanic eruptions.
Uses & applications
Historically used for making sharp cutting tools, arrowheads, and blades; currently utilized in ornamental jewelry, decorative objects, and experimental surgical scalpels.
Geological facts
Despite its glass-like appearance and lack of a true crystalline structure, it is classified as a naturally occurring rock rather than a true mineral.
Field identification & locations
Easily identified by its glassy texture, deep black color, and signature conchoidal fracture patterns; found globally in regions with recent volcanic activity.
