Rabejacite is an extremely rare secondary uranium mineral found primarily at the Rabejac mine in France. It typically forms as thin, bright yellow crystalline crusts or aggregates associated with other uranium-bearing minerals in sedimentary deposits.
Is this rabejacite?
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 rabejacite with a known reference. Rabejacite 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. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: yellow, amber yellow.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: acicular, aggregates, nodular.
Often confused with
Rabejacite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Rabejacite leaves white, Autunite leaves pale yellow.
How to tell apart: Streak differs, so Rabejacite leaves white, Uranopilite leaves pale yellow; luster reads vitreous on Rabejacite and silky on Uranopilite.
Often found alongside rabejacite
Minerals reported to co-occur with rabejacite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₂(UO₂)₄O₄(SO₄)₂·8H₂O
- Mohs hardness
- 3
- Density
- 4.1 g/cm³
- Colors
- YellowAmber yellow
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Acicular, aggregates, nodular
- Cleavage
- None
- Fluorescence
- Light yellow under SW and LW UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A rare secondary mineral in the oxidation zone of uranium deposits, formed by alteration of uraninite
Where rockhounds find rabejacite
Classic worldwide localities
- France, from the Rabéjac uranium deposit, seven km south-southeast of Lodève, and at the Mas-d’Alary uranium deposit, three km south-southeast of Lodève, Hérault
- La Creusa, near Les Marécottes, Valais, Switzerland
- Jáchymov (Joachimsthal), Czech Republic
Field-hunting tip
Where it forms: A rare secondary mineral in the oxidation zone of uranium deposits, formed by alteration of uraninite. If you start seeing gypsum, johannite, uraninite in float, you are in the right ground. Typical habit: acicular, aggregates, nodular. Train your eye for that shape before scanning the outcrop.
Common questions
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Find rabejacite on the map
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