Uranocircite is a brilliant yellow secondary uranium mineral often found as thin, square, tabular crystals or micaceous flakes. It is highly sought after by collectors for its striking neon-green fluorescence under ultraviolet light. Due to its radioactive nature, it should always be handled with care and stored in a secure, isolated container.

Hardness

2-2.5

Mohs

Luster

Pearly

Streak

Yellow

Transparency

Translucent

mineraluncommonAutunite Group family

Uranocircite

Hardness: 2-2.5
Luster: Pearly
Streak: Yellow
Transparency: Translucent

Is this uranocircite?

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 uranocircite with a known reference. Uranocircite sits at Mohs 2-2.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Uranocircite leaves a yellow streak.
3
Read the luster
Hold the specimen under a strong light. Uranocircite typically shows a pearly luster.
4
Match the color range
Compare against the expected color range: yellow, greenish-yellow.
5
Look at form & habit
Crystal system: tetragonal. Typical habit: tabular crystals, micaceous aggregates.

Often confused with

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

mineral

Autunite

Mohs 2-2.5

How to tell apart: Streak differs — Uranocircite leaves yellow, Autunite leaves pale yellow.

How to tell apart: Streak differs — Uranocircite leaves yellow, Torbernite leaves pale green; luster reads pearly on Uranocircite and vitreous on Torbernite.

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Often found alongside uranocircite

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

All properties

Chemical formula: Ba(UO₂)₂(PO₄)₂·10-12H₂O
Mohs hardness: 2-2.5
Density: 3.5 g/cm³
Colors: Yellow Greenish-yellow
Streak: Yellow
Luster: Pearly
Transparency: Translucent
Crystal system: Tetragonal
Crystal habit: Tabular Crystals, Micaceous Aggregates
Cleavage: Perfect Basal
Fluorescence: Bright Yellow-green Under UV
Rarity: Uncommon
Uses: Collector
Host rock: Oxidized Zones of Uranium Deposits
Typical price: $20-150 for thumbnail to small cabinet specimens

Where rockhounds find uranocircite

Classic worldwide localities

Bergen, Germany
Cornwall, England
Massif Central, France
Czech Republic

Field-hunting tip

Look in oxidized zones of uranium deposits country — that is the host setting where uranocircite typically forms. If you start seeing autunite, torbernite, uraninite in float, you are in the right ground. Field specimens usually show a tabular crystals, micaceous aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify uranocircite?+

Mohs hardness is 2-2.5. It typically shows a pearly luster. The streak is yellow. Common colors include yellow, greenish-yellow.

Where is uranocircite found?+

Notable localities include Bergen, Germany; Cornwall, England; Massif Central, France; Czech Republic.

How much is uranocircite worth?+

Typical asking prices fall in the range of $20-150 for thumbnail to small cabinet specimens. Quality, size, and provenance can move individual specimens well outside that range.

Is uranocircite safe to handle?+

This mineral is radioactive. It contains toxic constituents. Radioactive material; emits ionizing radiation and potential radon gas. Wash hands thoroughly after handling, avoid ingestion or inhalation of dust, and store in a lead-lined container away from living areas. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like uranocircite?+

Uranocircite is most often confused with Autunite, Torbernite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with uranocircite?+

Uranocircite commonly co-occurs with Autunite, Torbernite, Uraninite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does uranocircite form in?+

Uranocircite typically forms in oxidized zones of uranium deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is uranocircite used for?+

Uranocircite is used in collector.

Find uranocircite on the map

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