Iangreyite is a very rare aluminum phosphate mineral typically found as small, thin, pearly white plates or crusts. It is most commonly identified in phosphate-rich mineral assemblages, requiring professional chemical analysis for positive identification due to its similarity to other rare phosphates.
Is this iangreyite?
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 iangreyite with a known reference. Iangreyite sits at Mohs 3 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Iangreyite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Iangreyite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: white, pale yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy crystals, crusts, aggregates.
Often confused with
Iangreyite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside iangreyite
Minerals reported to co-occur with iangreyite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Al₇(PO₄)₄(OH)₉·2H₂O
- Mohs hardness
- 3
- Density
- 2.95 g/cm³
- Colors
- Streak
- White
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Platy Crystals, Crusts, Aggregates
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Phosphate-rich Pegmatites and Hydrothermal Veins
- Typical price
- $50-300 per specimen
Where rockhounds find iangreyite
Classic worldwide localities
- Ninghanboun Hills, Western Australia
- Santa Rita mine, Minas Gerais, Brazil
Field-hunting tip
Look in phosphate-rich pegmatites and hydrothermal veins country — that is the host setting where iangreyite typically forms. If you start seeing wavellite, variscite, crandallite in float, you are in the right ground. Field specimens usually show a platy crystals, crusts, aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find iangreyite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
