igneous

Snowflake Obsidian

Obsidian with Spherulitic Cristobalite (SiO2)

Hardness: 5-5.5 (Mohs scale), Color: Black with white or gray flower-like patterns, Luster: Vitreous/Glassy, Crystal Structure: Amorphous (glassy) with cristobalite inclusions, Specific Gravity: 2.3-2.6

Hardness: 5-5

Identified May 28, 2026More igneous →

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Physical properties

Formation & geological history

Snowflake obsidian is an extrusive igneous rock formed when felsic lava cools rapidly with minimal crystal growth. The 'snowflakes' are inclusions of the mineral cristobalite (a polymorph of silicon dioxide) that formed as the glass began to devitrify over time.

Uses & applications

Primarily used for jewelry (cabochons, beads), decorative carvings, meditation stones, and metaphysical tools. In antiquity, it was used for sharp tools and weapons.

Geological facts

Unlike most rocks, obsidian is technically a 'mineraloid' because it is volcanic glass rather than a true crystal. The snowflake pattern signifies the transition of glass back into a crystalline state, a process known as devitrification.

Field identification & locations

Identify by its glassy texture, conchoidal fracture, and distinctive white radiator-shaped splotches. It is commonly found in volcanic regions of Utah, Mexico, and Iceland. To identify, look for a smooth, non-porous surface that feels like heavy glass.

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Fluorapatite (Ca5(PO4)3F)

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Dark Igneous Rock (Likely Basalt or Diabase)

Basalt (extrusive igneous rock) or Diabase (intrusive igneous rock - also known as Dolerite), largely composed of plagioclase feldspar, pyroxene (augite), and sometimes olivine and amphibole. Exact mineralogy would require thin section analysis.

Igneous

Dalmatian Jasper

Aplite with Arfvedsonite inclusions

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Magnetite

Iron(II,III) oxide (Fe3O4)

mineral

Blue Apatite

Apatite (Group), Ca5(PO4)3(F,Cl,OH)

mineral

Sodalite

Sodalite - Na8(Al6Si6O24)Cl2

mineral