mineral

Blue Obsidian (Cullet Glass)

Silicon Dioxide (Amorphous Glass)

AI-generated identification · may be incorrect

Hardness of 5.5 on the Mohs scale, vibrant blue color, vitreous luster, amorphous crystal structure (no true crystal lattice), conchoidal fracture, specific gravity around 2.4-2.6

Identified August 2, 2026More mineral →

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Physical properties

Hardness of 5.5 on the Mohs scale, vibrant blue color, vitreous luster, amorphous crystal structure (no true crystal lattice), conchoidal fracture, specific gravity around 2.4-2.6

Formation & geological history

Formed artificially as a byproduct of industrial glass manufacturing (cullet glass), though natural volcanic glass (obsidian) forms from rapidly cooling lava

Uses & applications

Commonly sold to rockhounds, used in decorative lapidary work, wire-wrapping jewelry, and as a display specimen

Geological facts

While often sold to unsuspecting buyers as 'natural blue obsidian,' volcanic obsidian naturally occurs almost exclusively in black, dark brown, or grey. Brightly colored obsidian like this is almost always man-made cullet glass.

Field identification & locations

Easily identified by its glass-like conchoidal fractures, bubbles trapped inside the material, and vibrant unnatural hue. Found worldwide near glass manufacturing waste sites or rock shops