mineral

Green Obsidian Slag Glass

Silicon Dioxide (Amorphous Glass)

Hardness of 5.5 on the Mohs scale, vibrant emerald green color, vitreous luster, amorphous crystal structure with conchoidal fracture.

Identified October 23, 2026More mineral →

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Physical properties

Hardness of 5.5 on the Mohs scale, vibrant emerald green color, vitreous luster, amorphous crystal structure with conchoidal fracture.

Formed as industrial byproduct waste during high-temperature glass manufacturing processes.

Commonly collected as decorative lapidary rough, used for glass-knapping practice, or crafted into ornamental objects.

Often mistakenly sold to novice collectors as rare green obsidian, though true green volcanic glass is extremely rare.

Identified by conchoidal fracture, bubbles trapped inside the matrix, and lack of true crystal cleavage; found globally near historical glassworks.

Gneiss or Schist

Gneiss or Mica Schist with Garnet

Limonite

FeO(OH)•nH2O

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

Feldspar

Feldspar Group (Tectosilicate, e.g., KAlSi3O8)

Tumbled granite

Granite, a coarse-grained felsic intrusive igneous rock

Pegmatite with Tourmaline and Quartz

Igneous Pegmatite