Parauranophane is a rare secondary uranium silicate typically found as delicate, needle-like crystals or vibrant yellow radiating sprays. It is most easily distinguished from its dimorph, uranophane, through X-ray diffraction analysis, as they are visually near-identical. Collectors should handle specimens with care due to their significant radioactive content.
Is this parauranophane?
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 parauranophane with a known reference. Parauranophane sits at Mohs 2-3 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Parauranophane leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Parauranophane typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: yellow, lemon-yellow, orange-yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: acicular crystals, radiating sprays, fan-shaped aggregates, coatings.
Often confused with
Parauranophane vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Parauranophane leaves yellow, Uranophane leaves pale yellow; luster reads pearly on Parauranophane and vitreous on Uranophane.
How to tell apart: Luster reads pearly on Parauranophane and vitreous on Soddyite.
Often found alongside parauranophane
Minerals reported to co-occur with parauranophane. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca(UO₂)₂(SiO₃OH)₂·5H₂O
- Mohs hardness
- 2-3
- Density
- 4.1 g/cm³
- Streak
- Yellow
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Acicular Crystals, Radiating Sprays, Fan-shaped Aggregates, Coatings
- Cleavage
- Perfect
- Fluorescence
- Green Under SW UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Uranium-bearing Deposits
- Typical price
- $50-500 thumbnail, $300-2000 cabinet
Where rockhounds find parauranophane
Classic worldwide localities
- Wölsendorf, Germany
- Margnac, France
- Rössing, Namibia
- Katanga, DR Congo
Field-hunting tip
Look in oxidized zones of uranium-bearing deposits country — that is the host setting where parauranophane typically forms. If you start seeing uraninite, gummite, autunite in float, you are in the right ground. Field specimens usually show a acicular crystals, radiating sprays, fan-shaped aggregates, coatings habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find parauranophane on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
