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. Streak: pale yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: pearly.
- 4Match the color rangeCompare against the expected color range: green.
- 5Look at form & habitCrystal system: monoclinic. 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: Luster reads pearly on Metauranocircite and vitreous, pearly on {001} on Autunite.
How to tell apart: Luster reads pearly on Metauranocircite and vitreous, subadamantine, waxy, pearly on cleavages; becoming dull on dehydration to metatorbernite on Torbernite.
How to tell apart: Streak differs, so 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
- 3.95 g/cm³
- Colors
- Streak
- Pale yellow
- Luster
- Pearly
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular crystals, micaceous aggregates, crusts
- Cleavage
- Perfect basal
- Fluorescence
- Fluorescent
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Secndary mineral derived from phosphatic uraninite deposits
Where rockhounds find metauranocircite
Classic worldwide localities
- Bergen, Falkenstein, Vogtland, Sachsen (Saxony), Germany (type locality)
Field-hunting tip
Where it forms: Secndary mineral derived from phosphatic uraninite deposits. If you start seeing autunite, torbernite, uraninite in float, you are in the right ground. Typical habit: tabular crystals, micaceous aggregates, crusts. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify metauranocircite?+
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Is metauranocircite safe to handle?+
What rocks look like metauranocircite?+
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Find metauranocircite on the map
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