Zeunerite is a vibrant secondary uranium mineral often forming delicate, square-shaped tabular crystals. It is highly valued by radioactive mineral collectors for its intense green color and brilliant fluorescence under ultraviolet light, though it is chemically unstable and tends to dehydrate into meta-zeunerite.
Is this zeunerite?
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 zeunerite with a known reference. Zeunerite sits at Mohs 2.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: pale green.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: green, emerald green.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: micaceous, scaly, tabular.
Often confused with
Zeunerite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside zeunerite
Minerals reported to co-occur with zeunerite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu(UO₂)₂(AsO₄)₂·10-12H₂O
- Mohs hardness
- 2.5
- Density
- 3.47 g/cm³
- Colors
- Streak
- Pale green
- Luster
- Vitreous
- Transparency
- Transparent, becoming translucent on dehydration
- Crystal system
- Tetragonal
- Crystal habit
- Micaceous, scaly, tabular
- Cleavage
- On {001}, perfect; on {100}, distinct
- Rarity
- Rare
- Uses
- Collector
- Host rock
- An uncommon secondary mineral in the oxidized zone of arsenic-bearing hydrothermal uranium deposits
Where rockhounds find zeunerite
Classic worldwide localities
- Dexter mine, Calf Mesa, San Rafael district, Emery Co., Utah, USA
- Majuba Hill mine, Antelope district, Pershing Co., Nevada, USA
- Various of the Colorado Plateau-type U-V deposits, USA
- Time of study is relatively rare, although most meta-zeunerite is a dehydration product of pre-existing zeunerite
- Walpurgis vein, Weisser Hirsch mine, Neustädtel-Schneeberg, Saxony, Germany
- Sailauf, northeast of Aschaffenburg, Bavaria, Germany
Field-hunting tip
Where it forms: An uncommon secondary mineral in the oxidized zone of arsenic-bearing hydrothermal uranium deposits. If you start seeing olivenite, mansfieldite, scorodite in float, you are in the right ground. Typical habit: micaceous, scaly, tabular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify zeunerite?+
Where is zeunerite found?+
Is zeunerite safe to handle?+
What rocks look like zeunerite?+
What minerals are found with zeunerite?+
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Find zeunerite on the map
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