igneous
Snowflake Obsidian
Spherulitic Obsidian (primarily SiO2 with Cristobalite inclusions)
Hardness: 5-5.5 on Mohs scale; Color: Black with white or gray 'snowflake' patches; Luster: Vitreous (glassy); Crystal Structure: Amorphous (glass) with crystalline inclusions; Cleavage: none (conchoidal fracture); Specific Gravity: 2.35–2.60.
- Hardness
- 5-5
- Color
- Black with white or gray 'snowflake' patches
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 5-5.5 on Mohs scale; Color: Black with white or gray 'snowflake' patches; Luster: Vitreous (glassy); Crystal Structure: Amorphous (glass) with crystalline inclusions; Cleavage: none (conchoidal fracture); Specific Gravity: 2.35–2.60.
Formation & geological history
Formed through the rapid cooling of felsic lava. The 'snowflakes' are spherulites of white cristobalite (a type of quartz) that form as the glass begins to devitrify over time.
Uses & applications
Used primarily in jewelry (cabochons, beads), decorative carvings, and as a popular palm stone for mineral collectors and metaphysical practitioners.
Geological facts
Unlike minerals, obsidian is a volcanic glass and technically a 'mineraloid' because it lacks a crystalline structure. The white patches represent the process of the glass returning to a more stable crystalline state.
Field identification & locations
Identify by its glassy black base and distinct radiating white clusters. Commonly found in volcanic regions like Utah (USA), Mexico, and Iceland. In the field, look for smooth, sharp edges where it has chipped.
