Metauranocircite is a rare barium uranyl phosphate mineral that typically forms as thin, yellow-green tabular crystals or micaceous crusts. It is most easily identified by its intense yellow-green fluorescence under ultraviolet light. Collectors should treat it with strict safety protocols due to its radioactive nature and uranium content.
Is this metauranocircite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch metauranocircite with a known reference. Metauranocircite sits at Mohs 2-2.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Metauranocircite leaves a pale yellow streak.
- 3Read the lusterHold the specimen under a strong light. Metauranocircite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellow-green.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: tabular crystals, micaceous aggregates, crusts.
Often confused with
Metauranocircite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Metauranocircite leaves pale yellow, Torbernite leaves pale green; luster reads pearly on Metauranocircite and vitreous on Torbernite.
How to tell apart: Streak differs — Metauranocircite leaves pale yellow, Meta-autunite leaves yellow.
Often found alongside metauranocircite
Minerals reported to co-occur with metauranocircite. 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)₂·6H₂O
- Mohs hardness
- 2-2.5
- Density
- 3.5-3.7 g/cm³
- Colors
- Streak
- Pale Yellow
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Tetragonal
- Crystal habit
- Tabular Crystals, Micaceous Aggregates, Crusts
- Cleavage
- Perfect Basal
- Fluorescence
- Vivid Yellow-green Under UV Light
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Uranium-bearing Hydrothermal Veins
- Typical price
- $50-300 per specimen depending on crystal size and quality
Where rockhounds find metauranocircite
Classic worldwide localities
- Bergen, Saxony, Germany
- Margnac mine, France
- Wheal Basset, Cornwall, England
- Musonoi mine, DR Congo
Field-hunting tip
Look in uranium-bearing hydrothermal veins country — that is the host setting where metauranocircite 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, crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find metauranocircite on the map
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