igneous
Green obsidian (likely molded or heat-treated glass-like specimen)
Volcanic glass; predominantly rhyolitic composition (silica-rich amorphous SiO₂)
AI-generated identification · may be incorrectDark olive-green, translucent at thin edges, vitreous luster, conchoidal-looking fractures, no visible crystals or cleavage; Mohs hardness about 5–5.5, specific gravity ~2.3–2.6. The regular fluted edges and apparent layered shaping suggest it may be artificially cut or molded rather than natural obsidian.
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Physical properties
Dark olive-green, translucent at thin edges, vitreous luster, conchoidal-looking fractures, no visible crystals or cleavage; Mohs hardness about 5–5.5, specific gravity ~2.3–2.6. The regular fluted edges and apparent layered shaping suggest it may be artificially cut or molded rather than natural obsidian.
Formation & geological history
Natural obsidian forms when silica-rich lava cools rapidly, commonly during Quaternary volcanic eruptions; exact origin cannot be established from the image. It is found near rhyolitic volcanic fields, especially in the western United States, Mexico, Armenia, and Iceland.
Uses & applications
Used for ornaments, lapidary carvings, jewelry, blades, and collectibles; green material is often sold decoratively. If this is man-made glass, it has little geological or gem value.
Geological facts
Obsidian is technically volcanic glass rather than a crystalline mineral. Natural pieces commonly show sharp conchoidal fractures and flow banding; transparent green material may also be peridot-colored glass or slag.
Field identification & locations
Check for bubbles, perfectly uniform color, molded ridges, or smooth artificial edges—these favor glass. Natural obsidian is typically irregular, sharply fractured, and may show flow bands or tiny mineral inclusions.
