Zippeite is a secondary uranium sulfate mineral that typically forms as bright yellow to orange crusts or delicate acicular sprays in the oxidized zones of uranium mines. Collectors value it for its vivid fluorescence under long-wave ultraviolet light, but it requires careful handling due to its radioactivity.
Is this zippeite?
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 zippeite with a known reference. Zippeite 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: yellow white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: yellow, golden yellow, orange red, reddish brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: encrustations, pulverulent.
Often confused with
Zippeite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Zippeite leaves yellow white, Johannite leaves pale green.
How to tell apart: Streak differs, so Zippeite leaves yellow white, Uranopilite leaves pale yellow; luster reads vitreous on Zippeite and silky on Uranopilite.
Often found alongside zippeite
Minerals reported to co-occur with zippeite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K₂[(UO₂)₄(SO₄)₂O₂(OH)₂](H₂O)₄
- Mohs hardness
- ~2
- Density
- 4.8 g/cm³
- Streak
- Yellow white
- Luster
- Vitreous
- Transparency
- Semitransparent
- Crystal system
- Monoclinic
- Crystal habit
- Encrustations, pulverulent
- Cleavage
- Perfect
- Fluorescence
- Bright yellow under SW and LW UV
- Rarity
- Uncommon
- Uses
- Collector
- Host rock
- An uncommon secondary mineral, in part post-mine, in oxidized uranium deposits
Where rockhounds find zippeite
Classic worldwide localities
- Diamond Joe and Remington mines, Idaho Springs district, Clear Creek Co., and in the Telegraph, Wood, and Kirk mines, Gilpin Co., Colorado, USA
- Apex mine, Reese River district, Lander Co., Nevada, USA
- Jáchymov (Joachimsthal), Czech Republic
- Nowa Ruda, Lower Silesia, Poland
- Cornwall, at the Gunnislake mine, Calstock, England
- South Terras mine, St. Stephen-in-Brannel, England
Field-hunting tip
Where it forms: An uncommon secondary mineral, in part post-mine, in oxidized uranium deposits. If you start seeing uranopilite, natrozippeite, nickelzippeite in float, you are in the right ground. Typical habit: encrustations, pulverulent. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify zippeite?+
Where is zippeite found?+
Is zippeite safe to handle?+
What rocks look like zippeite?+
What minerals are found with zippeite?+
What kind of rock does zippeite form in?+
What is zippeite used for?+
Find zippeite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
