Uranosilite is a rare uranyl silicate mineral known for its distinct acicular or needle-like crystal habit often forming radiating sprays. Due to its radioactive nature and scarcity, it is highly sought after by advanced mineral collectors specializing in uranium secondary minerals.
Is this uranosilite?
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 uranosilite with a known reference. Uranosilite sits at Mohs 3 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Uranosilite leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Uranosilite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: yellow, pale yellow.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: acicular crystals, radiating sprays.
Often confused with
Uranosilite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Kasolite is the harder of the two (Mohs 4-5 vs. 3); luster reads pearly on Uranosilite and greasy on Kasolite.
How to tell apart: Streak differs — Uranosilite leaves yellow, Uranophane leaves pale yellow; luster reads pearly on Uranosilite and vitreous on Uranophane.
Often found alongside uranosilite
Minerals reported to co-occur with uranosilite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pb(UO₂)₄Si₂O₁₁·5H₂O
- Mohs hardness
- 3
- Density
- 4.2 g/cm³
- Colors
- Streak
- Yellow
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Acicular Crystals, Radiating Sprays
- Cleavage
- Perfect in One Direction
- Fluorescence
- Bright Green Under SW UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Uranium-bearing Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find uranosilite
Classic worldwide localities
- Uspenskoye deposit, Kazakhstan
Field-hunting tip
Look in oxidized zones of uranium-bearing deposits country — that is the host setting where uranosilite typically forms. If you start seeing uraninite, kasolite, calcite in float, you are in the right ground. Field specimens usually show a acicular crystals, radiating sprays habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find uranosilite on the map
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