Wilhelmvierlingite is a rare phosphate mineral typically found as small, thin plates or radiating groups within phosphate-rich pegmatites. It is most recognized from the Hagendorf-South locality in Germany where it occurs as a secondary mineral during the alteration of primary phosphate species.
Is this wilhelmvierlingite?
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 wilhelmvierlingite with a known reference. Wilhelmvierlingite sits at Mohs 4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: pale yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: yellow, brownish yellow.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: aggregates, fibrous, radial.
Often confused with
Wilhelmvierlingite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Childrenite is the harder of the two (Mohs 5 vs. 4); streak differs, so Wilhelmvierlingite leaves pale yellow, Childrenite leaves white.
How to tell apart: Eosphorite is the harder of the two (Mohs 5 vs. 4); streak differs, so Wilhelmvierlingite leaves pale yellow, Eosphorite leaves white.
Often found alongside wilhelmvierlingite
Minerals reported to co-occur with wilhelmvierlingite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaMnFe(PO₄)₂(OH)·2H₂O
- Mohs hardness
- 4
- Density
- 2.58 g/cm³
- Colors
- Streak
- Pale yellow
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Aggregates, fibrous, radial
- Cleavage
- On {010}, perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A rare secondary mineral in a complex zoned granite pegmatite
Where rockhounds find wilhelmvierlingite
Classic worldwide localities
- Hagendorf, Bavaria, Germany
Field-hunting tip
Where it forms: A rare secondary mineral in a complex zoned granite pegmatite. If you start seeing rockbridgeite, zwieselite in float, you are in the right ground. Typical habit: aggregates, fibrous, radial. Train your eye for that shape before scanning the outcrop.
Common questions
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What rocks look like wilhelmvierlingite?+
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Find wilhelmvierlingite on the map
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