Fervanite is a rare hydrated iron vanadium oxide typically found as fibrous coatings or acicular clusters in vanadium-rich sandstone deposits. Collectors typically search for it as thin yellow-to-brown crusts within the secondary oxidation zones of uranium-vanadium mines in the Colorado Plateau.
Is this fervanite?
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 fervanite with a known reference. Fervanite 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. Fervanite leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Fervanite typically shows a earthy luster.
- 4Match the color rangeCompare against the expected color range: yellow, brownish-yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: fibrous, acicular, powdery crusts.
Often confused with
Fervanite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Luster reads earthy on Fervanite and dull on Carnotite.
How to tell apart: Luster reads earthy on Fervanite and vitreous on Pascoite.
How to tell apart: Fervanite is noticeably harder (Mohs 2.5-3 vs. approx 1); streak differs — Fervanite leaves yellow, Hewettite leaves brownish red; luster reads earthy on Fervanite and pearly on Hewettite.
Often found alongside fervanite
Minerals reported to co-occur with fervanite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe₄V₄O₁₆·5H₂O
- Mohs hardness
- 2.5-3
- Density
- 2.8-2.9 g/cm³
- Colors
- Streak
- Yellow
- Luster
- Earthy
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Fibrous, Acicular, Powdery Crusts
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Sedimentary Sandstone Uranium-vanadium Deposits
- Typical price
- $20-150 per specimen
Where rockhounds find fervanite
Classic worldwide localities
- Montrose County, Colorado, USA
- San Juan County, Utah, USA
- Grand County, Utah, USA
Field-hunting tip
Look in sedimentary sandstone uranium-vanadium deposits country — that is the host setting where fervanite typically forms. If you start seeing carnotite, hewettite, gypsum in float, you are in the right ground. Field specimens usually show a fibrous, acicular, powdery crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find fervanite on the map
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