igneous
Mahogany Obsidian
Obsidian (Volcanic Glass with Hematite inclusions)
Hardness: 5-5.5 (Mohs scale); Color: Black with reddish-brown streaks or splotches; Luster: Vitreous/Glassy; Structure: Amorphous (non-crystalline); Fracture: Conchoidal; Specific Gravity: 2.35-2.6
- Hardness
- 5-5
- Color
- Black with reddish-brown streaks or splotches
- Luster
- Vitreous/Glassy
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Physical properties
Hardness: 5-5.5 (Mohs scale); Color: Black with reddish-brown streaks or splotches; Luster: Vitreous/Glassy; Structure: Amorphous (non-crystalline); Fracture: Conchoidal; Specific Gravity: 2.35-2.6
Formation & geological history
Formed from rapidly cooling felsic lava where the cooling process is so fast that crystals cannot grow. The reddish color is caused by trace amounts of Iron (Hematite/Magnetite) included during formation.
Uses & applications
Used primarily for jewelry (cabochons, beads), decorative carvings, and as a healing crystal in metaphysical practices. Historically used for making sharp cutting tools.
Geological facts
Mahogany obsidian is distinct because of its swirling 'mahogany' patterns which are unique to each stone. It lacks a crystal structure, technically making it a mineraloid rather than a true mineral.
Field identification & locations
Identify by its glassy texture, conchoidal fracture (curved surfaces), and distinctive brown-on-black pattern. Commonly found in areas with geologically recent volcanic activity like the American West (Oregon, California) and Mexico.
