Bassetite is a rare hydrated iron uranyl phosphate that typically occurs as thin, yellow-green tabular crystals. It is frequently found in the oxidation zones of uranium-bearing hydrothermal veins and is highly prized by collectors for its brilliant fluorescence.
Is this bassetite?
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 bassetite with a known reference. Bassetite sits at Mohs 2-3 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Bassetite leaves a pale yellow streak.
- 3Read the lusterHold the specimen under a strong light. Bassetite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellowish-green, brownish-yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, micaceous aggregates, crusts.
Often confused with
Bassetite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Luster reads vitreous on Bassetite and pearly on Autunite.
How to tell apart: Streak differs — Bassetite leaves pale yellow, Meta-autunite leaves yellow; luster reads vitreous on Bassetite and pearly on Meta-autunite.
How to tell apart: Streak differs — Bassetite leaves pale yellow, Torbernite leaves pale green.
Often found alongside bassetite
Minerals reported to co-occur with bassetite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe²⁺(UO₂)₂(PO₄)₂·8H₂O
- Mohs hardness
- 2-3
- Density
- 3.37 g/cm³
- Streak
- Pale Yellow
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals, Micaceous Aggregates, Crusts
- Cleavage
- Perfect Basal
- Fluorescence
- Bright Yellowish-green Under UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Veins in Granite, Oxidized Uranium Deposits
- Typical price
- $20-150 thumbnail, $200+ cabinet specimen
Where rockhounds find bassetite
Classic worldwide localities
- Wheal Basset, Cornwall, England
- Loděnice, Czech Republic
- Sabugal, Portugal
- Schneeberg, Germany
Field-hunting tip
Look in hydrothermal veins in granite, oxidized uranium deposits country — that is the host setting where bassetite typically forms. If you start seeing torbernite, uraninite, autunite 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 bassetite on the map
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