Shumwayite is a rare uranyl sulfate mineral typically found as small, vibrant yellow tabular crystals in oxidized uranium deposits. It is best identified through its association with other secondary uranium minerals and its occurrence in arid mining environments. Due to its radioactivity and solubility, it requires careful storage in a dry environment.
Is this shumwayite?
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 shumwayite with a known reference. Shumwayite 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: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: pale greenish yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, radial aggregates.
Often confused with
Shumwayite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside shumwayite
Minerals reported to co-occur with shumwayite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (UO₂)₂(SO₄)₂·5H₂O
- Mohs hardness
- ~2
- Density
- 3.844 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular crystals, radial aggregates
- Cleavage
- Perfect on {011}
- Fluorescence
- Fluoresces bright greenish white under SW & LW UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In efflorescent crusts formed by hydration-oxidation weathering of primary uranium minerals (esp. uraninite) by acidic solutions derived from the decomposition of associated sulfides
Where rockhounds find shumwayite
Classic worldwide localities
- Green Lizard and Giveaway-Simplot mines, Red Canyon, White Canyon mining district, San Juan County, Utah, USA
Field-hunting tip
Where it forms: In efflorescent crusts formed by hydration-oxidation weathering of primary uranium minerals (esp. uraninite) by acidic solutions derived from the decomposition of associated sulfides. If you start seeing calcite, gypsum, plášilite in float, you are in the right ground. Typical habit: tabular crystals, radial aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify shumwayite?+
Where is shumwayite found?+
Is shumwayite safe to handle?+
What rocks look like shumwayite?+
What minerals are found with shumwayite?+
What kind of rock does shumwayite form in?+
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Find shumwayite on the map
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