igneous
Apache Tear (Obsidian)
Volcanic glass (SiO2 - Silicon Dioxide)
Hardness: 5 to 5.5 on Mohs scale; Color: Black, appearing translucent smoky brown when held to light; Luster: Vitreous/glassy; Structure: Amorphous (non-crystalline); Cleavage: Conchoidal fracture.
- Hardness
- 5 to 5
- Color
- Black, appearing translucent smoky brown when held to light
- Luster
- Vitreous/glassy
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Physical properties
Hardness: 5 to 5.5 on Mohs scale; Color: Black, appearing translucent smoky brown when held to light; Luster: Vitreous/glassy; Structure: Amorphous (non-crystalline); Cleavage: Conchoidal fracture.
Formation & geological history
Formed when felsic lava cools rapidly with minimal water content, preventing crystal growth. They are rounded nodules found within gray perlite matrices, typically from Tertiary-aged volcanic deposits.
Uses & applications
Used in jewelry as beads or cabochons, for ornamental carvings, and by collectors. Historically used for making tools and arrowheads.
Geological facts
Legend says they formed from the tears of Apache women mourning warriors who jumped off a cliff rather than be captured; the tears froze into these dark stones.
Field identification & locations
Identified by their rounded 'pebble' shape, glassy texture, and smoky translucency when back-lit. Commonly found in the American Southwest, particularly Arizona and New Mexico.
