igneous

Snowflake Obsidian

Vitreous volcanic silicate rock (SiO2) with Spherulite inclusions

Hardness: 5-5.5 (Mohs scale); Color: Black with white or gray patches; Luster: Vitreous/Glassy; Structure: Amorphous (non-crystalline) glass with phenocrysts; Cleavage: None (Conchoidal fracture); Gravity: 2.3-2.6.

Hardness: 5-5
Color: Black with white or gray patches
Luster: Vitreous/Glassy

Identified May 3, 2026More igneous →

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Physical properties

Formation & geological history

Formed when felsic lava cools rapidly with minimal crystal growth, though the white 'snowflakes' are inclusions of cristobalite (a polymorph of quartz) produced through devitrification (partial crystallization).

Uses & applications

Commonly used in lapidary work for cabochons, beads, jewelry, and small carvings. Historically used for making sharp tools like scrapers and arrowheads.

Geological facts

The white patterns that look like snowflakes are known as spherulites. Unlike true obsidian which is entirely glass, this variety has begun the chemical process of turning back into a rock through crystallization.

Field identification & locations

Identify by its characteristic glassy black base and mottled white patterns. Often found in volcanic regions of Utah, Iceland, Mexico, and Italy. Collectors look for high contrast between the 'snow' and the '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

Magnetite

Iron(II,III) oxide (Fe3O4)

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Sodalite - Na8(Al6Si6O24)Cl2

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Blue Apatite

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

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Magnetite

Magnetite (Fe3O4)

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