igneous
Obsidian
Volcanic Glass
AI-generated identification · may be incorrectHardness of 5 to 5.5 on the Mohs scale, deep black color, 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, 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 sharp cutting tools and arrowheads; currently used in jewelry, ornamental objects, and experimental surgical scalpel blades.
Geological facts
Because it contains no true minerals, obsidian is technically a mineraloid rather than a mineral. Its razor-sharp edges can be thinner than man-made steel blades.
Field identification & locations
Easily identified by its glass-like appearance, jet-black color, and characteristic curved conchoidal fracture patterns.
