igneous
Mahogany Obsidian
Volcanic Glass with Hematite/Magnetite inclusions
Hardness: 5-5.5 (Mohs scale); Color: Black with reddish-brown streaks or mottling; Luster: Vitreous (glassy); Crystal Structure: Amorphous (non-crystalline); Fracture: Conchoidal; Specific Gravity: 2.3-2.6
- Hardness
- 5-5
- Color
- Black with reddish-brown streaks or mottling
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 5-5.5 (Mohs scale); Color: Black with reddish-brown streaks or mottling; Luster: Vitreous (glassy); Crystal Structure: Amorphous (non-crystalline); Fracture: Conchoidal; Specific Gravity: 2.3-2.6
Formation & geological history
Formed as an extrusive igneous rock when rhyolitic lava cools rapidly with minimal crystal growth. The mahogany color is caused by high concentrations of iron oxides like hematite or magnetite during the cooling process.
Uses & applications
Commonly used in jewelry (beads, cabochons), ornamental carvings, and holistic/metaphysical practices. Historically used for sharp tools due to its conchoidal fracture.
Geological facts
Mahogany Obsidian behaves exactly like glass because it has no internal crystalline structure. Native American tribes used it for arrowheads and trade goods. It is spiritually associated with grounding and protection.
Field identification & locations
Identify by its distinct brick-red to dark brown streaks against a black background and its very glassy, smooth feel. Commonly found in areas with recent volcanic activity such as the Western USA (Oregon, California), Mexico, and Japan.
