Alwilkinsite-(Y) is an exceptionally rare secondary uranium mineral typically found as small, delicate, yellow acicular crystals or efflorescent crusts. It forms in the oxidized zones of uranium-bearing pegmatites, often occurring as a late-stage alteration product.
Is this alwilkinsite-(y)?
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 alwilkinsite-(y) with a known reference. Alwilkinsite-(Y) 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-green.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: yellowish green.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: acicular crystals, efflorescent crusts.
Often confused with
Alwilkinsite-(Y) vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside alwilkinsite-(y)
Minerals reported to co-occur with alwilkinsite-(y). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Y(UO₂)₃(SO₄)₂O(OH)₃(H₂O)₇·7H₂O
- Mohs hardness
- 2-2.5
- Density
- 3.371 g/cm³
- Colors
- Streak
- Pale yellow-green
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Acicular crystals, efflorescent crusts
- Cleavage
- Perfect ∥ [010], probably on {102}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- granite pegmatite
Where rockhounds find alwilkinsite-(y)
Classic worldwide localities
- Blue Lizard mine, Red Canyon, White Canyon district, San Juan County, Utah, USA
Field-hunting tip
Where it forms: granite pegmatite. If you start seeing calcite, dickite, gypsum in float, you are in the right ground. Typical habit: acicular crystals, efflorescent crusts. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify alwilkinsite-(y)?+
Where is alwilkinsite-(y) found?+
Is alwilkinsite-(y) safe to handle?+
What rocks look like alwilkinsite-(y)?+
What minerals are found with alwilkinsite-(y)?+
What kind of rock does alwilkinsite-(y) form in?+
What is alwilkinsite-(y) used for?+
Find alwilkinsite-(y) on the map
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