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Rutherfordine is a secondary uranium mineral often found as an alteration product of uraninite in the oxidation zones of uranium-bearing deposits. It typically forms delicate, yellow, needle-like or bladed crystals, though it is more frequently encountered as earthy, powdery coatings on host rocks.

Hardness
2.5
Mohs
Luster
Dull to earthy, silky if fibrous
Streak
Yellow
Transparency
Semitransparent

Is this rutherfordine?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

  • 1
    Test the hardness
    Try to scratch rutherfordine with a known reference. Rutherfordine sits at Mohs 2.5, softer than the next harder reference, harder than the previous one.
  • 2
    Check the streak
    Drag the specimen across an unglazed porcelain plate. Streak: yellow.
  • 3
    Read the luster
    Hold the specimen under a strong light. Luster: dull to earthy, silky if fibrous.
  • 4
    Match the color range
    Compare against the expected color range: brownish, brownish yellow, white, light brown orange, light yellow.
  • 5
    Look at form & habit
    Crystal system: orthorhombic. Typical habit: encrustations.

Often confused with

Rutherfordine vs. its common look-alikes, and how to tell them apart in the field.

Autunite mineral
mineral
Autunite
Mohs 2-2.5

How to tell apart: Streak differs, so Rutherfordine leaves yellow, Autunite leaves pale yellow; luster reads dull to earthy, silky if fibrous on Rutherfordine and vitreous, pearly on {001} on Autunite.

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Often found alongside rutherfordine

Minerals reported to co-occur with rutherfordine. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula
UO₂(CO₃)
Mohs hardness
2.5
Density
5.7 g/cm³
Colors
BrownishBrownish yellowWhiteLight brown orangeLight yellow
Streak
Yellow
Luster
Dull to earthy, silky if fibrous
Transparency
Semitransparent
Crystal system
Orthorhombic
Crystal habit
Encrustations
Cleavage
On {010}, perfect; on {001}, less perfect
Fluorescence
Weak yellow green under SW and LW UV
Rarity
Rare
Uses
Collector
Host rock
A secondary mineral formed as a weathering product of uraninite

Where rockhounds find rutherfordine

Classic worldwide localities

  • Beryl Mountain, Acworth, Sullivan Co., and in the Palermo mine, near North Groton, Grafton Co., New Hampshire, USA
  • Newry, Oxford Co., Maine, USA
  • Delta mine, Emery Co., and in the “C” group of claims and the Jomac mine, White Canyon district, San Juan Co., Utah, USA
  • Lucky Mc No. 20 mine, Wind River Basin, Fremont Co., Wyoming, USA
  • Uluguru Mountains, Morogoro district, Tanzania
  • Shinkolobwe, from Kalongwe, and in the Musonoi mine, near Kolwezi, Katanga Province, Congo (Shaba Province, Zaire)

Field-hunting tip

Where it forms: A secondary mineral formed as a weathering product of uraninite. If you start seeing uraninite, becquerelite, masuyite in float, you are in the right ground. Typical habit: encrustations. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify rutherfordine?+
Mohs hardness is 2.5. Luster: dull to earthy, silky if fibrous. The streak is yellow. Common colors include brownish, brownish yellow, white, light brown orange.
Where is rutherfordine found?+
Notable localities include Beryl Mountain, Acworth, Sullivan Co., and in the Palermo mine, near North Groton, Grafton Co., New Hampshire, USA; Newry, Oxford Co., Maine, USA; Delta mine, Emery Co., and in the “C” group of claims and the Jomac mine, White Canyon district, San Juan Co., Utah, USA; Lucky Mc No. 20 mine, Wind River Basin, Fremont Co., Wyoming, USA; Uluguru Mountains, Morogoro district, Tanzania.
Is rutherfordine safe to handle?+
Rutherfordine contains uranium or thorium and calls for real care. Contains uranium and is highly radioactive; handle with gloves, wash hands thoroughly after contact, and store in a lead-lined container away from living areas.
What rocks look like rutherfordine?+
Rutherfordine is most often confused with Autunite. A quick hardness test and a streak check separate the look-alikes faster than color alone.
What minerals are found with rutherfordine?+
Rutherfordine commonly co-occurs with Uraninite, Becquerelite, Masuyite, Schoepite, Kasolite, Curite. Spotting any of these in float or country rock is a useful trip signal.
What kind of rock does rutherfordine form in?+
Where it forms: A secondary mineral formed as a weathering product of uraninite. Working float back to the host body is the standard way to chase a fresh occurrence.
What is rutherfordine used for?+
Rutherfordine is used in collector.

Find rutherfordine on the map

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