Kasolite is a striking radioactive secondary uranium mineral often found as small, vibrant yellow acicular crystals or earthy crusts. It is most frequently collected by specialist radioactive mineral enthusiasts and is typically found in the oxidized zones of uranium ore bodies where it forms as an alteration product of uraninite.
Is this kasolite?
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 kasolite with a known reference. Kasolite sits at Mohs 4-5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Kasolite leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Kasolite typically shows a greasy luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellow-orange, brownish-yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: acicular crystals, radiated sprays, crusts.
Often confused with
Kasolite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Kasolite leaves yellow, Curite leaves orange; luster reads greasy on Kasolite and adamantine on Curite.
How to tell apart: Streak differs — Kasolite leaves yellow, Fourmarierite leaves orange-yellow; luster reads greasy on Kasolite and adamantine on Fourmarierite.
How to tell apart: Kasolite is noticeably harder (Mohs 4-5 vs. 2.5); luster reads greasy on Kasolite and adamantine on Becquerelite.
Often found alongside kasolite
Minerals reported to co-occur with kasolite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pb(UO₂)(SiO₄)·H₂O
- Mohs hardness
- 4-5
- Density
- 5.96 g/cm³
- Streak
- Yellow
- Luster
- Greasy
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Acicular Crystals, Radiated Sprays, Crusts
- Cleavage
- Perfect in One Direction
- Fluorescence
- Bright Yellow-green Under UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Uranium-bearing Deposits
- Typical price
- $50-500 thumbnail depending on matrix and crystal quality
Where rockhounds find kasolite
Classic worldwide localities
- Shinkolobwe, DR Congo
- Jachymov, Czech Republic
- Wutong Mine, China
- Moab, Utah, USA
Field-hunting tip
Look in oxidized zones of uranium-bearing deposits country — that is the host setting where kasolite typically forms. If you start seeing curite, soddyite, vandenbrandeite in float, you are in the right ground. Field specimens usually show a acicular crystals, radiated sprays, crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find kasolite on the map
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