igneous
Gold Sheen Obsidian
Volcanic Glass (SiO2 + Fe3O4 / Gas Inclusions)
Hardness: 5-5.5 on Mohs scale; Color: Black with a golden metallic shimmer; Luster: Vitreous to sub-metallic; Crystal structure: Amorphous (non-crystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.35-2.60
- Hardness
- 5-5
- Color
- Black with a golden metallic shimmer
- Luster
- Vitreous to sub-metallic
Identified More igneous →
Explore Gold Sheen Obsidian in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 5-5.5 on Mohs scale; Color: Black with a golden metallic shimmer; Luster: Vitreous to sub-metallic; Crystal structure: Amorphous (non-crystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.35-2.60
Formation & geological history
Formed from the rapid cooling of silica-rich (felsic) lava where tiny gas bubbles or magnetite micro-crystals are trapped at the surface, creating an optical sheen. Most deposits are relatively young geologically (Cenozoic era).
Uses & applications
Used primarily in lapidary arts for jewelry, beads, and cabochons. Historically used for making sharp tools like scalpels and arrowheads; currently used for decorative carvings and metaphysical collection.
Geological facts
The 'sheen' effect is officially known as aventurescence or chatoyancy. Obsidian is technically not a mineral but a 'mineraloid' because it lacks a regular internal atomic structure.
Field identification & locations
Identify in the field by its glassy texture and conchoidal (shell-like) fracturing; the golden sheen is most visible under direct light. Most common in volcanic regions like Mexico (Jalisco) and the United States (Oregon).
