Wölsendorfite is a rare secondary uranium mineral typically forming as an alteration product of uraninite. Collectors should look for its distinctive orange to red platy crystals often associated with fluorite or other secondary uranium minerals in oxidized vein deposits.
Is this wölsendorfite?
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 wölsendorfite with a known reference. Wölsendorfite sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Wölsendorfite leaves a yellowish-orange streak.
- 3Read the lusterHold the specimen under a strong light. Wölsendorfite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: orange, reddish-orange, red, yellow.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: platy crystals, granular aggregates, coatings.
Often confused with
Wölsendorfite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Wölsendorfite leaves yellowish-orange, Fourmarierite leaves orange-yellow; luster reads vitreous on Wölsendorfite and adamantine on Fourmarierite.
How to tell apart: Streak differs — Wölsendorfite leaves yellowish-orange, Curite leaves orange; luster reads vitreous on Wölsendorfite and adamantine on Curite.
How to tell apart: Streak differs — Wölsendorfite leaves yellowish-orange, Vandenbrandeite leaves light green.
Often found alongside wölsendorfite
Minerals reported to co-occur with wölsendorfite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Pb,Ca)₆U₂O₇(OH)₆·2H₂O
- Mohs hardness
- 3-4
- Density
- 5.6-5.8 g/cm³
- Streak
- Yellowish-orange
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Platy Crystals, Granular Aggregates, Coatings
- Cleavage
- Perfect in One Direction
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Uranium-bearing Hydrothermal Veins
- Typical price
- $50-500 thumbnail depending on matrix and crystallization
Where rockhounds find wölsendorfite
Classic worldwide localities
- Wölsendorf, Bavaria, Germany
- Shinkolobwe, Democratic Republic of the Congo
- Great Bear Lake, Canada
- Lakeview, Oregon, USA
Field-hunting tip
Look in uranium-bearing hydrothermal veins country — that is the host setting where wölsendorfite typically forms. If you start seeing fluorite, uraninite, gummite in float, you are in the right ground. Field specimens usually show a platy crystals, granular aggregates, coatings habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find wölsendorfite on the map
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