igneous
Obsidian
Volcanic glass
AI-generated identification · may be incorrectHardness of 5 to 5.5 on the Mohs scale, deep blue to 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 blue to black color, vitreous luster, amorphous crystal structure with conchoidal fracture.
Formation & geological history
Formed from rapidly cooling felsic lava extruded from a volcano, lacking time to grow mineral crystals.
Uses & applications
Used for ornamental objects, arrowheads, surgical scalpels, and gemstone collections.
Geological facts
Despite being considered a mineraloid rather than a true mineral, it has been used by humans for toolmaking for millennia.
Field identification & locations
Identify by its glassy luster, smooth conchoidal fracture, and complete lack of cleavage. Found globally near recent volcanic activity.
