Paulkellerite is a very rare secondary uranium phosphate mineral found in oxidized zones of uranium deposits. It typically forms small, vibrant yellow to yellow-green tabular or bladed crystals and is a highly sought-after species for micromount collectors due to its extreme scarcity.
Is this paulkellerite?
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 paulkellerite with a known reference. Paulkellerite 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. Paulkellerite leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Paulkellerite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellow-green.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: bladed to tabular crystals.
Often confused with
Paulkellerite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Paulkellerite leaves yellow, Autunite leaves pale yellow; luster reads vitreous on Paulkellerite and pearly on Autunite.
How to tell apart: Luster reads vitreous on Paulkellerite and pearly on Meta-autunite.
Often found alongside paulkellerite
Minerals reported to co-occur with paulkellerite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K₂Fe³⁺₃(UO₂)₄(PO₄)₄(OH)₃·11H₂O
- Mohs hardness
- 2
- Density
- 4.95 g/cm³
- Colors
- Streak
- Yellow
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Bladed to Tabular Crystals
- Cleavage
- Perfect On {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Uranium-bearing Veins
- Typical price
- $200-1000+ per specimen
Where rockhounds find paulkellerite
Classic worldwide localities
- Replete mine, San Juan County, Utah, USA
Field-hunting tip
Look in hydrothermal uranium-bearing veins country — that is the host setting where paulkellerite typically forms. If you start seeing uraninite, goethite, jarosite in float, you are in the right ground. Field specimens usually show a bladed to tabular crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify paulkellerite?+
Where is paulkellerite found?+
How much is paulkellerite worth?+
Is paulkellerite safe to handle?+
What rocks look like paulkellerite?+
What minerals are found with paulkellerite?+
What kind of rock does paulkellerite form in?+
What is paulkellerite used for?+
Find paulkellerite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
