Uranopolycrase is a rare radioactive member of the euxenite group, typically found as an accessory mineral in granite pegmatites. It often presents as dark, metallic-looking prismatic crystals that are frequently metamict due to internal radiation damage.

Hardness

5-6

Mohs

Luster

Adamantine

Streak

Brown

Transparency

Opaque

mineralrareEuxenite Group family

Uranopolycrase

Hardness: 5-6
Luster: Adamantine
Streak: Brown
Transparency: Opaque

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Is this uranopolycrase?

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 uranopolycrase with a known reference. Uranopolycrase sits at Mohs 5-6, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: brown.
3
Read the luster
Hold the specimen under a strong light. Luster: adamantine.
4
Match the color range
Compare against the expected color range: brown red.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: euhedral crystals.

Often confused with

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

mineral

Euxenite-(Y)

Mohs 5.5-6.5

How to tell apart: Streak differs, so Uranopolycrase leaves brown, Euxenite-(Y) leaves yellowish, grayish, or reddish brown; luster reads adamantine on Uranopolycrase and brilliant submetallic, waxy to resinous on fractures on Euxenite-(Y).

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Often found alongside uranopolycrase

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

All properties

Chemical formula: UTi₂O₆
Mohs hardness: 5-6
Density: 5.5-6 g/cm³
Colors: Brown red
Streak: Brown
Luster: Adamantine
Transparency: Opaque
Crystal system: Orthorhombic
Crystal habit: Euhedral crystals
Cleavage: {100}, good
Rarity: Rare
Uses: Collector
Host rock: In a zoned pegmatite vein near the contact with granodiorite

Where rockhounds find uranopolycrase

Classic worldwide localities

San Piero in Campo, Elba, Italy

Field-hunting tip

Where it forms: In a zoned pegmatite vein near the contact with granodiorite. If you start seeing uranoan polycrase-, euxenite-, manganocolumbite in float, you are in the right ground. Typical habit: euhedral crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify uranopolycrase?+

Mohs hardness is 5-6. Luster: adamantine. The streak is brown. Common colors include brown red.

Where is uranopolycrase found?+

Notable localities include San Piero in Campo, Elba, Italy.

Is uranopolycrase safe to handle?+

Uranopolycrase contains uranium or thorium and calls for real care. This mineral is radioactive and contains uranium and thorium. Store in a shielded container away from living areas and handle with care, washing hands thoroughly after contact.

What rocks look like uranopolycrase?+

Uranopolycrase is most often confused with Euxenite-(Y). A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with uranopolycrase?+

Uranopolycrase commonly co-occurs with Uranoan polycrase-, Euxenite-, Manganocolumbite, Titanowodginite, Uranmicrolite, Beryl. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does uranopolycrase form in?+

Where it forms: In a zoned pegmatite vein near the contact with granodiorite. Working float back to the host body is the standard way to chase a fresh occurrence.

What is uranopolycrase used for?+

Uranopolycrase is used in collector.

Find uranopolycrase on the map

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