Chalcolite, more commonly known as Torbernite, is a striking bright green secondary uranium mineral. It is highly prized by collectors for its brilliant color and perfect micaceous crystal habit, though it requires careful storage and handling due to its radioactivity.
Is this chalcolite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch chalcolite with a known reference. Chalcolite sits at Mohs 2-2.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Chalcolite leaves a pale green streak.
- 3Read the lusterHold the specimen under a strong light. Chalcolite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: emerald green, grass green, leaf green.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: tabular crystals, micaceous, foliated, encrustations.
Often confused with
Chalcolite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside chalcolite
Minerals reported to co-occur with chalcolite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu(UO₂)₂(PO₄)₂·8-12H₂O
- Mohs hardness
- 2-2.5
- Density
- 3.22 g/cm³
- Streak
- Pale Green
- Luster
- Pearly
- Transparency
- Transparent
- Crystal system
- Tetragonal
- Crystal habit
- Tabular Crystals, Micaceous, Foliated, Encrustations
- Cleavage
- Perfect Basal
- Rarity
- Uncommon
- Uses
- Collector
- Host rock
- Oxidized Zones of Uranium Deposits
- Typical price
- $20-150 for thumbnail to cabinet specimens
Where rockhounds find chalcolite
1 mapped spotsClassic worldwide localities
- Cornwall, England
- Katanga, Democratic Republic of the Congo
- Musonoi Mine, Congo
- Schneeberg, Germany
Field-hunting tip
Look in oxidized zones of uranium deposits country — that is the host setting where chalcolite typically forms. If you start seeing autunite, uraninite, goethite in float, you are in the right ground. Field specimens usually show a tabular crystals, micaceous, foliated, encrustations habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Oregon — start trip planning there.
Common questions
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Find chalcolite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
