Chadwickite is a rare secondary uranium arsenate mineral that typically forms as small, yellow, tabular crystals or coatings on uranium-bearing ores. It is primarily sought after by specialist collectors of radioactive minerals due to its rarity and distinct fluorescence under ultraviolet light.
Is this chadwickite?
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 chadwickite with a known reference. Chadwickite sits at Mohs 2-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Chadwickite leaves a pale yellow streak.
- 3Read the lusterHold the specimen under a strong light. Chadwickite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, greenish-yellow.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: tabular crystals, crusts.
Often confused with
Chadwickite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Chadwickite leaves pale yellow, Meta-autunite leaves yellow; luster reads vitreous on Chadwickite and pearly on Meta-autunite.
How to tell apart: Streak differs, so Chadwickite leaves pale yellow, Torbernite leaves pale green.
How to tell apart: Streak differs, so Chadwickite leaves pale yellow, Zeunerite leaves pale green; luster reads vitreous on Chadwickite and pearly on Zeunerite.
Often found alongside chadwickite
Minerals reported to co-occur with chadwickite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (UO₂)(HAsO₄)·4H₂O
- Mohs hardness
- 2-3
- Density
- 4.6-4.8 g/cm³
- Colors
- Streak
- Pale Yellow
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Tetragonal
- Crystal habit
- Tabular Crystals, Crusts
- Cleavage
- Perfect Basal
- Fluorescence
- Bright Green Under UV Light
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Uranium Veins
- Typical price
- $50-300 per specimen
Where rockhounds find chadwickite
Classic worldwide localities
- Jáchymov, Czech Republic
- Great Bear Lake, Canada
- White Canyon, Utah, USA
Field-hunting tip
Look in hydrothermal uranium veins country, the host setting where chadwickite typically forms. If you start seeing uraninite, arsenopyrite, goethite in float, you are in the right ground. Field specimens usually show a tabular crystals, crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find chadwickite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
