Metahewettite is a rare hydrated calcium vanadate that typically forms as bright deep red earthy crusts or fibrous aggregates in vanadium-rich sandstone. It is most commonly found as an alteration product of hewettite in oxidized uranium-vanadium ore bodies. Collectors should handle specimens with care due to their friable nature and the potential toxicity of vanadium compounds.
Is this metahewettite?
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 metahewettite with a known reference. Metahewettite sits at Mohs 1.5-2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: maroon to brownish red.
- 3Read the lusterHold the specimen under a strong light. Luster: dull to somewhat silky.
- 4Match the color rangeCompare against the expected color range: red.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: fibrous, earthy, massive, or as capillary coatings.
Often confused with
Metahewettite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Metahewettite leaves maroon to brownish red, Hewettite leaves brownish red; luster reads dull to somewhat silky on Metahewettite and silky to adamantine on Hewettite.
How to tell apart: Streak differs, so Metahewettite leaves maroon to brownish red, Carnotite leaves strontian-yellow.
How to tell apart: Streak differs, so Metahewettite leaves maroon to brownish red, Vanoxite leaves brown black; luster reads dull to somewhat silky on Metahewettite and metallic on Vanoxite.
Often found alongside metahewettite
Minerals reported to co-occur with metahewettite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaV₆O₁₆·3H₂O
- Mohs hardness
- 1.5-2
- Density
- 2.94 g/cm³
- Colors
- Streak
- Maroon to brownish red
- Luster
- Dull to somewhat silky
- Transparency
- Semitransparent
- Crystal system
- Monoclinic
- Crystal habit
- Fibrous, earthy, massive, or as capillary coatings
- Cleavage
- Perfect on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- As an impregnation in sandstone (Colorado Plateau-type U–V deposits)
Where rockhounds find metahewettite
Classic worldwide localities
- Minasragra, Peru (type locality)
Field-hunting tip
Where it forms: As an impregnation in sandstone (Colorado Plateau-type U–V deposits). If you start seeing hewettite, gypsum, selenium in float, you are in the right ground. Typical habit: fibrous, earthy, massive, or as capillary coatings. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify metahewettite?+
Where is metahewettite found?+
Is metahewettite safe to handle?+
What rocks look like metahewettite?+
What minerals are found with metahewettite?+
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Find metahewettite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
