Snowflake Obsidian
Obsidian var. Snowflake (contains Phenocrysts of Cristobalite) · Semi-Precious Gemstone / Decorative Stone
Crystal System
Amorphous (Glassy); inclusions are Tetragonal
Mineral Group
Silicates (Volcanic Glass)
Chemical Formula
70–75% SiO2, plus MgO, Fe3O4 (Volcanic Glass) with SiO2 (Cristobalite) inclusions
Formation Process
Igneous. Forms from rapid cooling of felsic lava, preventing crystallization. The 'snowflakes' are spherulites of cristobalite formed through devitrification.
About This Crystal
A black volcanic glass featuring white or grayish radiating patches known as spherulites. It is opaque to translucent at edges with a smooth, vitreous luster.
Physical Characteristics
Color: Black with white 'snowflakes'; Streak: White; Cleavage: None; Fracture: Conchoidal; Specific Gravity: 2.35–2.6; Fluorescence: Generally inert.
Optical Properties
Isotropic (Singly refractive); Refractive Index: 1.48–1.51; Luster: Vitreous/Glassy; No pleochroism due to amorphous structure.
Hardness & Durability
Origin Region
Western USA (Utah, California), Mexico, Iceland, and Italy (Lipari Islands)
Hardness & Durability
Mohs Hardness: 5.0–5.5; Brittle tenacity; sensitive to sharp impacts which cause chipping due to conchoidal fracture.
Care & Maintenance
Clean with warm soapy water and a soft cloth; avoid ultrasonic cleaners and harsh chemicals; store separately to prevent scratching from harder gems like quartz.
Rarity & Value
Common; very affordable. Values determined by the distribution and pattern of the white inclusions. Rarely treated.
Special Characteristics
Devitrification patterns (spherulites) that create the 'snowflake' effect; features a signature conchoidal fracture typical of natural glass.
Lore & History
Historically used for tool-making and mirrors; traditionally associated with the Root Chakra and believed to provide balance and purity in crystal healing lore.