igneous
Snowflake Obsidian
Volcanic Glass (felsic volcanic glass with cristobalite inclusions)
Hardness: 5-5.5 on the Mohs scale; Color: Black with white or grayish patch-like patterns resembling snowflakes; Luster: Vitreous to glassy; Structure: Amorphous (glassy matrix) with sphaerulitic inclusions of cristobalite; Cleavage: None (conchoidal fracture).
- Hardness
- 5-5
- Luster
- Vitreous to glassy
Identified More igneous →
Explore Snowflake Obsidian in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 5-5.5 on the Mohs scale; Color: Black with white or grayish patch-like patterns resembling snowflakes; Luster: Vitreous to glassy; Structure: Amorphous (glassy matrix) with sphaerulitic inclusions of cristobalite; Cleavage: None (conchoidal fracture).
Formation & geological history
Formed when silica-rich felsic lava cools rapidly with minimal crystal growth to form obsidian glass. Over time, partial devitrification occurs where spherulites of the mineral cristobalite (a silica polymorph) grow within the black glass matrix, creating the distinct 'snowflake' patterns.
Uses & applications
Used extensively in jewelry making, ornamental carvings, polished stones, beads, and metaphysical/healing practices. Historically used by ancient cultures to make sharp tools, arrowheads, and blades.
Geological facts
Snowflake Obsidian represents a stage in the slow transformation of unstable volcanic glass back into stable crystalline quartz. The white spots are called spherulites, which are radial aggregates of needle-like cristobalite crystals.
Field identification & locations
Easily recognized by its glossy black background dotted with white, flower-like, or snowflake-shaped inclusions. Commonly found in volcanic regions such as the United States (Utah, Oregon, California), Mexico, Iceland, and Italy. Collectors value well-defined, distinct snowflake patterns on deep black backgrounds.
