Uroxite is a rare secondary uranium mineral typically found as small, fibrous to radiating yellow crusts in oxidized ore zones. Because it is both radioactive and chemically unstable, collectors should handle specimens with specialized equipment and store them in secure, airtight display containers.
Is this uroxite?
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 uroxite with a known reference. Uroxite 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. Uroxite leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Uroxite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellowish-green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: fibrous, radiated aggregates.
Often confused with
Uroxite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Uroxite leaves yellow, Uranophane leaves pale yellow; luster reads pearly on Uroxite and vitreous on Uranophane.
How to tell apart: Kasolite is the harder of the two (Mohs 4-5 vs. 2-3); luster reads pearly on Uroxite and greasy on Kasolite.
Often found alongside uroxite
Minerals reported to co-occur with uroxite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- UO₂·2MoO₃·4H₂O
- Mohs hardness
- 2-3
- Density
- 3.2 g/cm³
- Colors
- Streak
- Yellow
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Fibrous, Radiated Aggregates
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Uranium-molybdenum Deposits
- Typical price
- $50-500 depending on specimen size and radioactivity levels
Where rockhounds find uroxite
Classic worldwide localities
- Jachymov, Czech Republic
- Katanga, DR Congo
- Utah, USA
Field-hunting tip
Look in oxidized zones of uranium-molybdenum deposits country — that is the host setting where uroxite typically forms. If you start seeing uraninite, gummite, molybdenite in float, you are in the right ground. Field specimens usually show a fibrous, radiated aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find uroxite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
