Barnesite is a rare sodium vanadium oxide hydrate typically found as dark, reddish-brown platy crystals or crusts in sedimentary uranium-vanadium deposits. It is a secondary mineral that forms through the oxidation of primary vanadium minerals in arid environments, most notably in the Colorado Plateau region of the United States.
Is this barnesite?
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 barnesite with a known reference. Barnesite sits at Mohs 3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: brownish red.
- 3Read the lusterHold the specimen under a strong light. Luster: adamantine, less brilliant after exposure.
- 4Match the color rangeCompare against the expected color range: dark red, brown red.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy crystals, crusts, radial aggregates.
Often confused with
Barnesite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Barnesite leaves brownish red, Corvusite leaves purplish blue-black; luster reads adamantine, less brilliant after exposure on Barnesite and “lusterous” on Corvusite.
How to tell apart: Barnesite is noticeably harder (Mohs 3 vs. ~1); luster reads adamantine, less brilliant after exposure on Barnesite and silky to adamantine on Hewettite.
How to tell apart: Barnesite is noticeably harder (Mohs 3 vs. <2); streak differs, so Barnesite leaves brownish red, Navajoite leaves brown.
Often found alongside barnesite
Minerals reported to co-occur with barnesite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂V₆O₁₆·3H₂O
- Mohs hardness
- 3
- Density
- 3.09-3.15 g/cm³
- Streak
- Brownish red
- Luster
- Adamantine, less brilliant after exposure
- Transparency
- Semitransparent
- Crystal system
- Monoclinic
- Crystal habit
- Platy crystals, crusts, radial aggregates
- Cleavage
- {001}, perfect; {100}, {010}, fair
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In small cavities and fractures and as interstitial filling in sandstone in the oxidized zone of a vanadiferous uranium deposit, possibly formed as an oxidation product of hewettite (Cactus Rat mines, Utah, USA)
Where rockhounds find barnesite
Classic worldwide localities
- Cactus Rat mine group, Yellow Cat district, 24 km southeast of Thompson, Grand Co., Utah and The Fish, Eureka Co., Nevada, USA
Field-hunting tip
Where it forms: In small cavities and fractures and as interstitial filling in sandstone in the oxidized zone of a vanadiferous uranium deposit, possibly formed as an oxidation product of hewettite (Cactus Rat mines, Utah, USA). If you start seeing metahewettite, thenardite, bokite in float, you are in the right ground. Typical habit: platy crystals, crusts, radial aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify barnesite?+
Where is barnesite found?+
Is barnesite safe to handle?+
What rocks look like barnesite?+
What minerals are found with barnesite?+
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Find barnesite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
