Deloryite is a rare secondary uranium mineral typically found as small, green, platy crystals in oxidized zones. It is highly sought after by collectors of radioactive minerals for its distinct aesthetic and composition, primarily occurring at the Shinkolobwe mine.
Is this deloryite?
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 deloryite with a known reference. Deloryite sits at Mohs 4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: green.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to greasy.
- 4Match the color rangeCompare against the expected color range: dark green, black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy crystals.
Often confused with
Deloryite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Deloryite leaves green, Malachite leaves pale green; luster reads vitreous to greasy on Deloryite and adamantine to vitreous; silky if fibrous; dull to earthy if massive on Malachite.
How to tell apart: Streak differs, so Deloryite leaves green, Cuprosklodowskite leaves greenish yellow; luster reads vitreous to greasy on Deloryite and dull to silky in aggregates on Cuprosklodowskite.
Often found alongside deloryite
Minerals reported to co-occur with deloryite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₄(UO₂)(MoO₄)₂(OH)₆
- Mohs hardness
- 4
- Density
- 4.9 g/cm³
- Colors
- Streak
- Green
- Luster
- Vitreous to greasy
- Transparency
- Transparent to nearly opaque
- Crystal system
- Monoclinic
- Crystal habit
- Platy crystals
- Cleavage
- Perfect on {010} and {100}; good on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Very rare in the oxidized portion of a uranium deposit in sandstone
Where rockhounds find deloryite
Classic worldwide localities
- Cap Garonne mine, near le Pradet, Var, France
Field-hunting tip
Where it forms: Very rare in the oxidized portion of a uranium deposit in sandstone. If you start seeing metazeunerite, atacamite, paratacamite in float, you are in the right ground. Typical habit: platy crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify deloryite?+
Where is deloryite found?+
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Find deloryite on the map
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