Vochtenite is a rare phosphate mineral in the autunite group typically found as thin, yellow to brownish-yellow platy crystals. It is primarily known from the oxidation zones of uranium-bearing pegmatites and is highly sought after by advanced radioactive mineral collectors.
Is this vochtenite?
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 vochtenite with a known reference. Vochtenite sits at Mohs ~2.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: pale brown.
- 3Read the lusterHold the specimen under a strong light. Luster: bronzy.
- 4Match the color rangeCompare against the expected color range: bronze brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: aggregates.
Often confused with
Vochtenite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads bronzy on Vochtenite and vitreous, pearly on {001} on Autunite.
How to tell apart: Luster reads bronzy on Vochtenite and vitreous, subadamantine, waxy, pearly on cleavages; becoming dull on dehydration to metatorbernite on Torbernite.
How to tell apart: Streak differs, so Vochtenite leaves pale brown, Meta-autunite leaves yellow; luster reads bronzy on Vochtenite and pearly to dull on Meta-autunite.
Often found alongside vochtenite
Minerals reported to co-occur with vochtenite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- FeFe(UO₂)₄(PO₄)₄(OH)·12-13H₂O
- Mohs hardness
- ~2.5
- Density
- 3.650 g/cm³
- Colors
- Streak
- Pale brown
- Luster
- Bronzy
- Transparency
- Opaque, translucent in thin fragments
- Crystal system
- Monoclinic
- Crystal habit
- Aggregates
- Cleavage
- On {010}, distinct
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A rare secondary mineral in the oxidized zone of a uranium-bearing Cu–Sn hydrothermal mineral deposit
Where rockhounds find vochtenite
Classic worldwide localities
- Wheal Basset, Illogan, Cornwall, England
Field-hunting tip
Where it forms: A rare secondary mineral in the oxidized zone of a uranium-bearing Cu–Sn hydrothermal mineral deposit. If you start seeing bassetite in float, you are in the right ground. Typical habit: aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
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Find vochtenite on the map
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