White Obsidian
Volcanic glass (~70-75% SiO2)
A pale, partly crystallized volcanic glass; genuinely white obsidian is uncommon and usually reflects devitrification or spherulitic growth in the glass.
- Mohs hardness
- 5-6
- Color
- White to cream, opaque to translucent
- Type
- igneous
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Overview
White Obsidian refers to pale, whitish volcanic glass. Pure white obsidian is genuinely uncommon, because the white usually comes from devitrification, the slow growth of microscopic crystals (often cristobalite spherulites) within the glass that scatter light and lighten the color.
The most familiar related material is snowflake obsidian, black glass speckled with white spherulites. Fully white pieces represent a more advanced or pervasive version of the same crystallization process.
Some material sold as white obsidian is actually manufactured glass, so authentic pieces should show natural texture and locality data.
Formation & geology
Obsidian forms when felsic lava cools rapidly into glass. Over time, or with slower cooling, the metastable glass can begin to crystallize, a process called devitrification. Tiny radiating crystals (spherulites) of cristobalite and feldspar nucleate within the glass.
Where these spherulites are abundant, the glass takes on a white to cream color, producing snowflake patterns or, when pervasive, an overall whitish stone. Such material is found in rhyolitic flows in places like the western United States (e.g., Utah, Oregon) and Mexico.
How to identify it
Color: White to cream, opaque where crystallized, sometimes translucent at thin edges.
Texture: May show gray-to-black glassy zones and rounded white spherulite patches (snowflake texture).
Luster: Vitreous to slightly silky; conchoidal fracture in glassy areas.
Hardness: ~5-6.
Streak: White.
Look-alikes: White chalcedony and milky quartz are harder (7) and lack glassy conchoidal fracture. Manufactured white glass is uniform and bubble-bearing; natural white obsidian shows spherulite texture and gradational color.
Uses & significance
White Obsidian (and snowflake obsidian) is used for tumbles, beads, cabochons, spheres, and carvings. The contrast of white spherulites against dark glass is especially valued in jewelry.
Metaphysically it is associated with purity, balance, and grounding, traditional claims rather than science. Devitrified volcanic glass (perlite/pearlstone) is also expanded industrially for lightweight aggregate and horticultural perlite, though that is a separate processed product.
Frequently asked questions
Is white obsidian real?
Genuine pale obsidian exists, but the white usually comes from devitrification (microscopic crystals); some "white obsidian" is actually manufactured glass.
How is it related to snowflake obsidian?
The same spherulite crystals that make snowflake patterns, when pervasive, can lighten the whole stone toward white.
How do I tell it from milky quartz?
Quartz is harder (7) and lacks the glassy conchoidal fracture of obsidian.
Why is pure white obsidian rare?
Extensive devitrification usually changes the glass into a stony rock, so fully white yet glassy pieces are uncommon.
White Obsidian guides
In-depth guides for identifying, valuing, and understanding White Obsidian.
