igneous

Snowflake Obsidian

Volcanic Glass with Cristobalite Inclusions

Hardness: 5-6 (Mohs), Color: Black with white or gray patches, Luster: Vitreous/Glassy, Structure: Amorphous (non-crystalline), Cleavage: None (conchoidal fracture), SG: 2.3-2.6

Identified May 29, 2026More igneous →

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Physical properties

Hardness: 5-6 (Mohs), Color: Black with white or gray patches, Luster: Vitreous/Glassy, Structure: Amorphous (non-crystalline), Cleavage: None (conchoidal fracture), SG: 2.3-2.6

Formation & geological history

Forms when silica-rich lava cools rapidly, preventing crystal growth. The 'snowflakes' are inclusions of the mineral cristobalite that formed as the glass began to devitrify. Found in volcanic areas throughout the Cenozoic and Quaternary periods.

Uses & applications

Used primarily in jewelry (cabochons, beads), decorative carvings, and as a popular stone for mineral collectors and metaphysical practitioners.

Geological facts

Unlike typical minerals, obsidian is a 'mineraloid' because it lacks a crystalline structure. The white spots represent the transformation of the glass back into a mineral, a process called devitrification.

Field identification & locations

Identified by its distinctive white 'snowflake' patches against a dark black glassy base. It is commonly found in areas of recent volcanic activity such as the Western United States (Utah, Oregon), Mexico, and Iceland.

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