Carnotite is a bright yellow, radioactive secondary mineral commonly found as earthy or powdery crusts in sandstone formations. It serves as an important secondary ore for uranium and vanadium, often replacing organic materials like fossilized wood within its host rock.
Is this carnotite?
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 carnotite with a known reference. Carnotite sits at Mohs 2 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Carnotite leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Carnotite typically shows a dull luster.
- 4Match the color rangeCompare against the expected color range: bright yellow, lemon yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: earthy, powdery, or as crusty coatings.
Often confused with
Carnotite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Luster reads dull on Carnotite and pearly on Tyuyamunite.
How to tell apart: Streak differs — Carnotite leaves yellow, Autunite leaves pale yellow; luster reads dull on Carnotite and pearly on Autunite.
How to tell apart: Streak differs — Carnotite leaves yellow, Uranophane leaves pale yellow; luster reads dull on Carnotite and vitreous on Uranophane.
Often found alongside carnotite
Minerals reported to co-occur with carnotite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K₂(UO₂)₂(VO₄)₂·3H₂O
- Mohs hardness
- 2
- Density
- 4.7-5.0 g/cm³
- Streak
- Yellow
- Luster
- Dull
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Earthy, Powdery, Or as Crusty Coatings
- Cleavage
- Perfect
- Rarity
- Common
- Uses
- Ore of Uranium, Ore of Vanadium, Collector Mineral
- Host rock
- Sedimentary Sandstone
- Typical price
- $10-50 per small specimen
Where rockhounds find carnotite
24 mapped spotsClassic worldwide localities
- Colorado Plateau, USA
- Utah, USA
- Katanga, DR Congo
- South Australia
U.S. states with carnotite
Each link opens a state-specific list of mapped rockhounding spots that produce carnotite.
Field-hunting tip
Look in sedimentary sandstone country — that is the host setting where carnotite typically forms. If you start seeing tyuyamunite, uraninite, gypsum in float, you are in the right ground. Field specimens usually show a earthy, powdery, or as crusty coatings habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Utah, Pennsylvania — start trip planning there.
Common questions
How do you identify carnotite?+
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Find carnotite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
