Frosted Obsidian
Volcanic glass (~70-75% SiO2), surface-textured
Natural obsidian with a frosted, matte surface produced by weathering, abrasion, or etching rather than a separate variety of glass.
- Mohs hardness
- 5-6
- Color
- Black to gray with a frosty, semi-translucent surface
- Type
- igneous
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Overview
Frosted Obsidian is ordinary obsidian whose glossy surface has been turned cloudy and matte. The frosting is a surface effect, not a change in the glass itself, caused by natural weathering, water and sand abrasion (beach or river tumbling), or deliberate sandblasting/acid etching.
The body of the stone remains true volcanic glass, usually black or gray, and a fresh fracture reveals the original glossy interior. "Frosted obsidian" sold commercially is often Apache tears or rough obsidian that has been etched or tumbled to a satin finish.
It is valued for its soft, ghostly appearance.
Formation & geology
The glass itself forms by rapid cooling of high-silica lava. The frosted surface develops afterward.
In nature, obsidian transported in streams or surf is repeatedly struck by sand and gravel, microscopically pitting the surface and scattering light into a frosty sheen. Prolonged exposure also allows slow hydration and chemical etching of the glass surface. Commercially, the same look is reproduced by tumbling with grit or by sandblasting/acid treatment.
How to identify it
Surface: Cloudy, satin, semi-translucent skin; under magnification it shows fine pitting or micro-fractures.
Interior: A chip or fresh break reveals glossy black or gray glass with conchoidal fracture, confirming it is obsidian.
Hardness: ~5-6.
Streak: White.
Look-alikes: Frosted quartz or beach glass can look similar, but obsidian's body is darker, warms quickly in the hand, and shows conchoidal fracture. Beach glass (man-made bottle glass) often retains seams or bubbles.
Uses & significance
Frosted Obsidian is used for tumbles, beads, pendants, and decorative pieces where a soft, non-reflective look is desired. The matte surface diffuses light attractively and hides fingerprints.
Metaphysically it carries the same grounding and protective associations as black obsidian, which are traditional beliefs rather than verified properties. The frosting is purely cosmetic and does not change the stone's composition or value beyond aesthetics.
Frequently asked questions
Is frosted obsidian a different mineral?
No. It is ordinary obsidian with a frosted surface caused by weathering, abrasion, or etching.
How is the frosting made?
By natural water-and-sand abrasion, surface hydration, or commercial tumbling, sandblasting, or acid etching.
Can I see the real glass?
Yes, a fresh chip reveals glossy black or gray glass beneath the matte skin.
Is it the same as beach glass?
Not necessarily. Beach glass is usually man-made bottle glass; frosted obsidian is natural volcanic glass with a darker body.
Frosted Obsidian guides
In-depth guides for identifying, valuing, and understanding Frosted Obsidian.
Frosted Obsidian identified by the community
Real specimens identified with Rock Identifier.
