Corvusite is a rare sodium calcium potassium oxide, typically purplish blue-black to greenish black. Associated minerals include carnotite, fervanite and roscoelite. It was first described from the Jack claim, La Sal Mountains, Grand Co., Utah, USA.
Is this corvusite?
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 corvusite with a known reference. Corvusite sits at Mohs 2.5-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Corvusite leaves a purplish blue-black streak.
- 3Read the lusterHold the specimen under a strong light. Corvusite typically shows a dull luster.
- 4Match the color rangeCompare against the expected color range: purplish blue-black, greenish black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: massive, earthy, crusts.
Often confused with
Corvusite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Corvusite is noticeably harder (Mohs 2.5-3 vs. approx 1); streak differs, so Corvusite leaves purplish blue-black, Hewettite leaves brownish red; luster reads dull on Corvusite and silky to adamantine on Hewettite.
How to tell apart: Streak differs, so Corvusite leaves purplish blue-black, Pascoite leaves yellow; luster reads dull on Corvusite and vitreous on Pascoite.
Often found alongside corvusite
Minerals reported to co-occur with corvusite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Na,Ca,K)₁₋ₓ(V⁵⁺,V⁴⁺,Fe²⁺)₈O₂₀·4H₂O
- Mohs hardness
- 2.5-3
- Density
- 2.82 g/cm³
- Streak
- Purplish Blue-black
- Luster
- Dull
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Massive, Earthy, Crusts
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Sedimentary Sandstone Uranium-vanadium Deposits
Where rockhounds find corvusite
3 mapped spotsClassic worldwide localities
- Colorado Plateau, USA
- Utah, USA
- New Mexico, USA
Field-hunting tip
Look in sedimentary sandstone uranium-vanadium deposits country, the host setting where corvusite typically forms. If you start seeing hewettite, pyrolusite, carnotite in float, you are in the right ground. Field specimens usually show a massive, earthy, crusts habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Utah. Start trip planning there.
Common questions
How do you identify corvusite?+
Where is corvusite found?+
Can I find corvusite in the United States?+
Is corvusite safe to handle?+
What rocks look like corvusite?+
What minerals are found with corvusite?+
What kind of rock does corvusite form in?+
What is corvusite used for?+
Find corvusite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
