igneous
Obsidian
Volcanic Glass (Silica-rich, SiO2)
AI-generated identification · may be incorrectHardness of 5 to 5.5 on the Mohs scale, black or dark gray 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, black or dark gray color, vitreous luster, amorphous crystal structure with conchoidal fracture.
Formation & geological history
Formed through the rapid cooling of felsic lava associated with volcanic eruptions, lacking sufficient time for crystal growth.
Uses & applications
Commonly used in jewelry, decorative items, and historically utilized for making sharp cutting tools like arrowheads and blades.
Geological facts
Despite being classified as a mineraloid rather than a true mineral, obsidian has been prized by human civilizations since the Stone Age for its razor-sharp edges.
Field identification & locations
Easily identified by its glass-like appearance, smooth curved fracture surfaces, and dark translucent to opaque nature; found globally near recent volcanic activity.
