Darwin Glass
Darwin Glass is impact glass (impactite), SiO₂-rich natural glass. In the hand, it rates 5.5 to 6 on the Mohs scale, and it runs white-green and olive. Pale-to-olive green frothy natural glass in twisted, ropy, bubbly shapes, stickier-looking and less sculpted than moldavite's crisp fern texture.
The geology.
Darwin Glass carries the formula SiO₂-rich natural glass. It belongs to the amorphous system. The trade files it under impact glass (impactite).
It sits at 5.5 to 6 on the Mohs scale. The surface reads vitreous to greasy. Light behaviour is translucent to transparent. Specific gravity runs 1.85 to 2.30 (often frothy). The streak is white. It breaks with conchoidal fracture.
Pale-to-olive green frothy natural glass in twisted, ropy, bubbly shapes, stickier-looking and less sculpted than moldavite's crisp fern texture.
Common cuts are twisted ropy fragments, frothy lumps or sculpted shards.
The origins.
Strewn field around Darwin Crater, western Tasmania, an impact about 800,000 years ago.
On value, the database notes: mid-range; large clean pieces are collector items.
Traditional associations.
In energy work traditions, sold alongside tektites with transformation themes, a quieter cousin of moldavite.
Included for completeness. Tradition is worth knowing about, and it is worth keeping separate from the mineralogy.
Spotting the real thing.
Pale-to-olive green frothy natural glass in twisted, ropy, bubbly shapes, stickier-looking and less sculpted than moldavite's crisp fern texture.
Less faked than moldavite but green bottle glass appears under the name, frothy ropy texture and Tasmanian sourcing matter.
| Looks like | How to tell them apart |
|---|---|
| Moldavite | Moldavite is bottle-green with etched fern ridges; Darwin glass is paler, frothier, and Tasmanian |
| Slag glass | Slag shows vivid colors and metallic specks; Darwin glass is consistently muted green with quartz-rich chemistry |
| Bottle glass | Molded surfaces, uniform clarity, no twisted ropy forms |
At-home tests.
These checks cost nothing. Daylight, a 10x loupe and a little patience are the whole kit for darwin glass.
| Test | What you should see |
|---|---|
| Look for bubbles | Frothy, twisted shapes with elongated bubbles |
| By eye | Lighter than typical glass when vesicular |
| Provenance | genuine material comes only from western Tasmania |
Stop short of anything that leaves a mark. A gemologist can answer the rest without damaging the stone.
Care & handling.
At 5.5 to 6 on the Mohs scale it handles careful wear but scratches against quartz and dust. Store it separately and take rings off before rough work.
It breaks with conchoidal fracture, which is worth knowing before you set it or drop it.
Skip the ultrasonic. Lukewarm water, mild soap and a soft cloth handle routine cleaning without risk.
A deeper look.
Extended detail on composition, sourcing, authentication and market value.
The physical record
The formula on record is SiO₂-rich natural glass. Crystal system: Amorphous. Specific gravity: 1.85 to 2.30 (often frothy). Streak: White. Cleavage and fracture: Conchoidal fracture.
How it reaches the market
Strewn field around Darwin Crater, western Tasmania, an impact about 800,000 years ago.
What it gets confused with
Moldavite: Moldavite is bottle-green with etched fern ridges; Darwin glass is paler, frothier, and Tasmanian. Slag glass: Slag shows vivid colors and metallic specks; Darwin glass is consistently muted green with quartz-rich chemistry. Bottle glass: Molded surfaces, uniform clarity, no twisted ropy forms.
What it is worth
Mid-range; large clean pieces are collector items.
Where buyers get caught
Less faked than moldavite but green bottle glass appears under the name, frothy ropy texture and Tasmanian sourcing matter.
One more thing
Darwin glass flew up to 100 km from its small crater, gram for gram one of the most efficient glass-flinging impacts known.
An education-first guide.
We do not carry darwin glass. This page exists because the question comes up and the honest answer is worth writing down, whether or not there is anything here to sell you.
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