Lepersonnite-(Gd) is a rare uranyl carbonate-silicate mineral found almost exclusively in the Shinkolobwe mine. It is highly prized by collectors for its vibrant yellow color, distinct bladed habit, and intense fluorescence under ultraviolet light.

Hardness

2-3

Mohs

Luster

Vitreous

Streak

Light yellow

Transparency

Transparent to translucent

mineralrare

Lepersonnite-(Gd)

Hardness: 2-3
Luster: Vitreous
Streak: Light yellow
Transparency: Transparent to translucent

Is this lepersonnite-(gd)?

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 lepersonnite-(gd) with a known reference. Lepersonnite-(Gd) sits at Mohs 2-3, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: light yellow.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: bright yellow.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: aggregates, encrustations, spherical.

Often confused with

Lepersonnite-(Gd) vs. its common look-alikes, and how to tell them apart in the field.

mineral

Schuilingite-(Nd)

Mohs 3.5

How to tell apart: Luster reads vitreous on Lepersonnite-(Gd) and adamantine on Schuilingite-(Nd).

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Often found alongside lepersonnite-(gd)

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

All properties

Chemical formula: [Ca₀.₅Gd₀.₅(H₂O)₁₈(OH)₁.₅][Gd(UO₂)₁₂(SiO₃OH)₂(CO₃)₄(OH)₁₀O₂(H₂O)₅]
Mohs hardness: 2-3
Density: 3.97 g/cm³
Colors: Bright yellow
Streak: Light yellow
Luster: Vitreous
Transparency: Transparent to translucent
Crystal system: Orthorhombic
Crystal habit: Aggregates, encrustations, spherical
Cleavage: Good on {1}
Rarity: Rare
Uses: Collector
Host rock: In the lower portion of the oxidation zone developed above uraninite-bearing dolomitic rocks

Where rockhounds find lepersonnite-(gd)

Classic worldwide localities

Shinkolobwe, Katanga Province, Congo (Shaba Province, Zaire)

Field-hunting tip

Where it forms: In the lower portion of the oxidation zone developed above uraninite-bearing dolomitic rocks. If you start seeing bijvoetite, sklodowskite, curite in float, you are in the right ground. Typical habit: aggregates, encrustations, spherical. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify lepersonnite-(gd)?+

Mohs hardness is 2-3. Luster: vitreous. The streak is light yellow. Common colors include bright yellow.

Where is lepersonnite-(gd) found?+

Notable localities include Shinkolobwe, Katanga Province, Congo (Shaba Province, Zaire).

Is lepersonnite-(gd) safe to handle?+

Lepersonnite-(Gd) contains uranium or thorium and calls for real care. Contains uranium and heavy rare earth elements; emits ionizing radiation and poses chemical toxicity risks. Handle with gloves and wash hands thoroughly after contact. Do not inhale dust or store in living areas.

What rocks look like lepersonnite-(gd)?+

Lepersonnite-(Gd) is most often confused with Schuilingite-(Nd). A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with lepersonnite-(gd)?+

Lepersonnite-(Gd) commonly co-occurs with Bijvoetite, Sklodowskite, Curite, Uranophane, Becquerelite, Rutherfordine. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does lepersonnite-(gd) form in?+

Where it forms: In the lower portion of the oxidation zone developed above uraninite-bearing dolomitic rocks. Working float back to the host body is the standard way to chase a fresh occurrence.

What is lepersonnite-(gd) used for?+

Lepersonnite-(Gd) is used in collector.

Find lepersonnite-(gd) on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.