igneous
Mahogany Obsidian
Obsidian with Hematite inclusions (SiO2 + Fe2O3)
Hardness: 5-5.5 (Mohs scale), Color: Black with reddish-brown streaks or spots, Luster: Vitreous (glassy), Crystal Structure: Amorphous (non-crystalline), Cleavage: None (conchoidal fracture), Specific Gravity: 2.35-2.6
- Hardness
- 5-5
Identified More igneous →
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Physical properties
Hardness: 5-5.5 (Mohs scale), Color: Black with reddish-brown streaks or spots, Luster: Vitreous (glassy), Crystal Structure: Amorphous (non-crystalline), Cleavage: None (conchoidal fracture), 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 mahogany color comes from magnetite or hematite inclusions. Formed in volcanic regions during the Cenozoic era.
Uses & applications
Commonly used in jewelry (cabochons and beads), ornamental carvings, crystal healing, and as a material for sharp tools or scalpels due to its fracture patterns.
Geological facts
Mahogany Obsidian is unique because its reddish swirls are caused by high concentrations of iron. Unlike many minerals, it is actually a natural volcanic glass rather than a true crystalline mineral.
Field identification & locations
Identified by its distinctive brown-red and black mottled appearance and its typical glassy, smooth surface. It is commonly found in regions with recent volcanic activity like Mexico, the United States (Oregon, Utah), and Japan.
