Sharpite is a rare secondary uranium mineral typically found as small, yellow, platy crystals or crusts in oxidized uranium deposits. It is best identified by its bright fluorescence under ultraviolet light and its association with other secondary uranium minerals in arid or hydrothermal environments.
Is this sharpite?
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 sharpite with a known reference. Sharpite sits at Mohs 2.5-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: pearly.
- 4Match the color rangeCompare against the expected color range: greenish yellow, olive green, grayish white.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: acicular, encrustations, radial.
Often confused with
Sharpite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads pearly on Sharpite and vitreous to pearly on cleavages on Liebigite.
How to tell apart: Streak differs, so Sharpite leaves yellow, Andersonite leaves white; luster reads pearly on Sharpite and vitreous to pearly on Andersonite.
Often found alongside sharpite
Minerals reported to co-occur with sharpite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca(UO₂)₃(CO₃)₄(H₂O)₃
- Mohs hardness
- 2.5-3
- Density
- 4.45 g/cm³
- Streak
- Yellow
- Luster
- Pearly
- Transparency
- Semitransparent
- Crystal system
- Orthorhombic
- Crystal habit
- Acicular, encrustations, radial
- Cleavage
- Perfect
- Fluorescence
- Strong yellow-green under UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A very rare secondary mineral formed in the oxide zone of hydrothermal uranium deposits
Where rockhounds find sharpite
Classic worldwide localities
- Shinkolobwe, Katanga Province, Congo (Shaba Province, Zaire)
- Kruth, Haut-Rhin, and in the Brugeaud mine, near Bessines, Haute-Vienne, France
Field-hunting tip
Where it forms: A very rare secondary mineral formed in the oxide zone of hydrothermal uranium deposits. If you start seeing uranophane, becquerelite, schoepite in float, you are in the right ground. Typical habit: acicular, encrustations, radial. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify sharpite?+
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Find sharpite on the map
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