igneous
Snowflake Obsidian
Volcanic Glass with Cristobalite inclusions (SiO2)
Hardness: 5-5.5 on Mohs scale. Color: Jet black with white or grayish patches ('snowflakes'). Luster: Vitreous to glassy. Structure: Amorphous (non-crystalline matrix) with radial spherulites of cristobalite. Cleavage: None, exhibits conchoidal fracture. Specific Gravity: 2.35-2.6.
- Hardness
- 5-5
- Color
- Jet black with white or grayish patches ('snowflakes')
- Luster
- Vitreous to glassy
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Physical properties
Hardness: 5-5.5 on Mohs scale. Color: Jet black with white or grayish patches ('snowflakes'). Luster: Vitreous to glassy. Structure: Amorphous (non-crystalline matrix) with radial spherulites of cristobalite. Cleavage: None, exhibits conchoidal fracture. Specific Gravity: 2.35-2.6.
Formation & geological history
Formed when felsic lava cools rapidly with minimum crystal growth, creating natural volcanic glass. Over time, devitrification occurs where parts of the glass recrystallize into cristobalite (a silica mineral) forming white, snowflake-like mineral inclusions.
Uses & applications
Popular for lapidary work, tumbled stones, jewelry (beads, cabochons), ornamental carvings, and holistic/crystal healing practices.
Geological facts
Because obsidian is glass rather than a true mineral, it has no crystal structure. The white 'snowflake' patterns are radial clusters of the silica mineral cristobalite. Ancient cultures used obsidian for razor-sharp surgical tools, arrowheads, and mirrors.
Field identification & locations
Look for a glassy, pitch-black surface interrupted by distinct white or pale gray patches resembling snowflakes. Commonly found in volcanic regions worldwide including Oregon, Utah, California (USA), Mexico, Iceland, and Japan.
