Walentaite is an extremely rare iron arsenate-phosphate mineral that typically forms as delicate, platy crystals or radial clusters. It is primarily found in the oxidation zones of complex granite pegmatites and is a prized target for advanced mineral collectors due to its scarcity and unique crystal form.
Is this walentaite?
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 walentaite with a known reference. Walentaite 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. Walentaite leaves a light green streak.
- 3Read the lusterHold the specimen under a strong light. Walentaite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: olive green, yellowish-green, brownish-green.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: platy crystals, radial aggregates.
Often confused with
Walentaite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Walentaite leaves light green, Pharmacosiderite leaves white; luster reads pearly on Walentaite and adamantine on Pharmacosiderite.
How to tell apart: Scorodite is the harder of the two (Mohs 3.5-4 vs. 2.5); streak differs — Walentaite leaves light green, Scorodite leaves white; luster reads pearly on Walentaite and vitreous to sub-adamantine on Scorodite.
Often found alongside walentaite
Minerals reported to co-occur with walentaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- H₄Fe³⁺₃(AsO₄)₂PO₄·4H₂O
- Mohs hardness
- 2.5
- Density
- 3.37 g/cm³
- Streak
- Light Green
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Platy Crystals, Radial Aggregates
- Cleavage
- Perfect On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Granite Pegmatites
- Typical price
- $50-300 per specimen
Where rockhounds find walentaite
Classic worldwide localities
- Hagendorf-Sud Pegmatite, Bavaria, Germany
- Tip Top Mine, South Dakota, USA
- Reaphook Hill, South Australia
Field-hunting tip
Look in granite pegmatites country — that is the host setting where walentaite typically forms. If you start seeing arsenopyrite, phosphosiderite, strengite in float, you are in the right ground. Field specimens usually show a platy crystals, radial aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find walentaite on the map
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