Paddlewheelite is a very rare uranyl carbonate mineral typically found as small, blue-green platy crystals or crusts. It is named for its unique crystal structure that resembles a paddlewheel. It is predominantly found in the historic mining district of Jáchymov, Czech Republic, associated with other secondary uranium minerals.
Is this paddlewheelite?
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 paddlewheelite with a known reference. Paddlewheelite sits at Mohs ~2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: very pale blue-green.
- 3Read the lusterHold the specimen under a strong light. Luster: sub-adamantine.
- 4Match the color rangeCompare against the expected color range: blue-green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy crystals, crusts.
Often confused with
Paddlewheelite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Paddlewheelite leaves very pale blue-green, Liebigite leaves yellow white; luster reads sub-adamantine on Paddlewheelite and vitreous to pearly on cleavages on Liebigite.
How to tell apart: Streak differs, so Paddlewheelite leaves very pale blue-green, Andersonite leaves white; luster reads sub-adamantine on Paddlewheelite and vitreous to pearly on Andersonite.
Often found alongside paddlewheelite
Minerals reported to co-occur with paddlewheelite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- MgCa₅Cu₂(UO₂)₄(CO₃)₁₂(H₂O)₃₃
- Mohs hardness
- ~2
- Density
- 2.497 g/cm³
- Colors
- Streak
- Very pale blue-green
- Luster
- Sub-adamantine
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Platy crystals, crusts
- Cleavage
- At least one perfect on {100}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- hydrothermal veins
Where rockhounds find paddlewheelite
Classic worldwide localities
- Prokop vein on the 5th level, Svornost (Concord) mine, Jáchymov District, Bohemia, Czech Republic
Field-hunting tip
Where it forms: hydrothermal veins. If you start seeing calcite, dolomite, chalcopyrite in float, you are in the right ground. Typical habit: platy crystals, crusts. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify paddlewheelite?+
Where is paddlewheelite found?+
Is paddlewheelite safe to handle?+
What rocks look like paddlewheelite?+
What minerals are found with paddlewheelite?+
What kind of rock does paddlewheelite form in?+
What is paddlewheelite used for?+
Find paddlewheelite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
