igneous
Red Obsidian
Volcanic Glass (Amorphous SiO2)
Mohs hardness of 5 to 5.5, deep red to dark brownish-red color with a stark white cristobalite inclusion at the tip, vitreous luster, conchoidal fracture with no crystal structure, and a specific gravity of around 2.35.
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Physical properties
Mohs hardness of 5 to 5.5, deep red to dark brownish-red color with a stark white cristobalite inclusion at the tip, vitreous luster, conchoidal fracture with no crystal structure, and a specific gravity of around 2.35.
Formation & geological history
Formed as an extrusive igneous rock when felsic lava cools rapidly with minimal crystal growth. The distinctive white tip is often a spherulite or cristobalite inclusion.
Uses & applications
Popular in crystal healing, lapidary arts, wire-wrapping, and as a collector's mineral specimen due to its striking two-tone color contrast.
Geological facts
Red obsidian gets its color from finely dispersed hematite or magnetite nanoparticles trapped within the glass matrix during rapid cooling.
Field identification & locations
Identified by its smooth, glassy appearance, sharp conchoidal edges, and the unique white inclusion at the apex. Often found in volcanic regions associated with rhyolitic flows.
