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, so Uranocircite leaves yellow, Autunite leaves pale yellow.

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

Compare →

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, 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.