igneous
Gold Sheen Obsidian
Obsidian (volcanic glass with SiO2 + gas inclusions)
Hardness: 5-5.5 (Mohs), Color: Black with golden shimmer, Luster: Vitreous/Glassy, Structure: Amorphous (non-crystalline), Cleavage: Conchoidal fracture
- Hardness
- 5-5
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Physical properties
Hardness: 5-5.5 (Mohs), Color: Black with golden shimmer, Luster: Vitreous/Glassy, Structure: Amorphous (non-crystalline), Cleavage: Conchoidal fracture
Formation & geological history
Formed from the rapid cooling of silica-rich rhyolitic lava. The gold sheen is caused by tiny bubbles of gas or water vapor trapped between layers as the lava flowed before solidifying.
Uses & applications
Commonly used in jewelry (cabochons), carved into figurines, or used in metaphysical practices. Historically used for sharp tools/scalpels due to its fracture patterns.
Geological facts
Unlike regular obsidian, sheen varieties show their luster only when light hits the surface at a specific angle. It is technically a mineraloid because it lacks a crystal structure.
Field identification & locations
Identify by the signature conchoidal (curved/shell-like) fracture and the chatoyant golden shimmer. Found prominently in volcanic areas like Mexico and the Western USA.
