Coconinoite is a rare, complex hydrated iron-aluminum-uranyl phosphate mineral that typically occurs as soft, powdery, or earthy yellow coatings on sandstone. It was first discovered in the uranium-bearing deposits of the Colorado Plateau and is highly sought after by collectors of radioactive minerals due to its restricted type localities.
Is this coconinoite?
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 coconinoite with a known reference. Coconinoite sits at Mohs 1-2 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Coconinoite leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Coconinoite typically shows a dull luster.
- 4Match the color rangeCompare against the expected color range: yellow, tan.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: fine-grained earthy or powdery aggregates.
Often confused with
Coconinoite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Coconinoite leaves yellow, Autunite leaves pale yellow; luster reads dull on Coconinoite and pearly on Autunite.
How to tell apart: Streak differs — Coconinoite leaves yellow, Torbernite leaves pale green; luster reads dull on Coconinoite and vitreous on Torbernite.
Often found alongside coconinoite
Minerals reported to co-occur with coconinoite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe³⁺₂Al₂(UO₂)(PO₄)₄(OH)₂·20H₂O
- Mohs hardness
- 1-2
- Density
- 2.8 g/cm³
- Streak
- Yellow
- Luster
- Dull
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Fine-grained Earthy or Powdery Aggregates
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Sandstone Hosted Uranium Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find coconinoite
Classic worldwide localities
- Coconino County, Arizona, USA
- San Juan County, Utah, USA
- Grand County, Utah, USA
Field-hunting tip
Look in sandstone hosted uranium deposits country — that is the host setting where coconinoite typically forms. If you start seeing gypsum, jarosite, uraninite in float, you are in the right ground. Field specimens usually show a fine-grained earthy or powdery aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify coconinoite?+
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How much is coconinoite worth?+
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Find coconinoite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
