Abernathyite is a rare secondary uranium mineral that typically occurs as small, yellow, square tabular crystals. It is most often found in the oxidized zones of uranium-bearing sandstone deposits and is highly prized by collectors for its brilliant fluorescence under ultraviolet light.
Is this abernathyite?
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 abernathyite with a known reference. Abernathyite sits at Mohs 2.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Abernathyite leaves a pale yellow streak.
- 3Read the lusterHold the specimen under a strong light. Abernathyite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: yellow, lemon yellow.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: tabular crystals, micaceous aggregates.
Often confused with
Abernathyite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Abernathyite leaves pale yellow, Meta-autunite leaves yellow.
How to tell apart: Streak differs — Abernathyite leaves pale yellow, Torbernite leaves pale green; luster reads pearly on Abernathyite and vitreous on Torbernite.
Often found alongside abernathyite
Minerals reported to co-occur with abernathyite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K(UO₂)(AsO₄)·3H₂O
- Mohs hardness
- 2.5
- Density
- 3.42 g/cm³
- Colors
- Streak
- Pale Yellow
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Tetragonal
- Crystal habit
- Tabular Crystals, Micaceous Aggregates
- Cleavage
- Perfect Basal
- Fluorescence
- Bright Yellow-green Under SW UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Sandstone, Uranium-bearing Sedimentary Rocks
- Typical price
- $50-300 per specimen depending on size and crystal quality
Where rockhounds find abernathyite
Classic worldwide localities
- Lucky Mc mine, Wyoming, USA
- Temple Mountain, Utah, USA
- Schneeberg, Germany
Field-hunting tip
Look in sandstone, uranium-bearing sedimentary rocks country — that is the host setting where abernathyite typically forms. If you start seeing uraninite, gypsum, meta-autunite 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
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Find abernathyite on the map
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