Metarauchite is a very rare secondary uranium-nickel arsenate mineral typically found as a result of the dehydration of rauchite. It commonly appears as small, thin, yellow tabular crystals or crusts within hydrothermal vein systems rich in nickel and uranium.
Is this metarauchite?
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 metarauchite with a known reference. Metarauchite sits at Mohs 2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: light green to pale yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous, pearly on (011).
- 4Match the color rangeCompare against the expected color range: yellow.
- 5Look at form & habitCrystal system: triclinic. Typical habit: tabular crystals, crusts.
Often confused with
Metarauchite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Metarauchite leaves light green to pale yellow, Rauchite leaves white.
How to tell apart: Streak differs, so Metarauchite leaves light green to pale yellow, Meta-autunite leaves yellow; luster reads vitreous, pearly on (011) on Metarauchite and pearly to dull on Meta-autunite.
Often found alongside metarauchite
Minerals reported to co-occur with metarauchite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ni(UO₂)₂(AsO₄)₂·8H₂O
- Mohs hardness
- 2
- Density
- 3.81 g/cm³
- Colors
- Streak
- Light green to pale yellow
- Luster
- Vitreous, pearly on (011)
- Transparency
- Transparent to translucent
- Crystal system
- Triclinic
- Crystal habit
- Tabular crystals, crusts
- Cleavage
- Perfect on (011)
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A secondary mineral in strongly oxidized polymetallic vein material
Where rockhounds find metarauchite
Classic worldwide localities
- Schweitzer vein of the Eduard mine, Jáchymov, Czech Republic
- Adam Heber Mine, Neustädtel, Schneeberg district, Germany
Field-hunting tip
Where it forms: A secondary mineral in strongly oxidized polymetallic vein material. If you start seeing metazeunierite, erythrite, gypsum in float, you are in the right ground. Typical habit: tabular crystals, crusts. Train your eye for that shape before scanning the outcrop.
Common questions
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Find metarauchite on the map
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