Phosphoferrite is a rare secondary phosphate mineral typically found in phosphate-rich granite pegmatites. It is often identified by its pale, often bluish-green prismatic crystals or crystalline crusts formed by the alteration of triphylite.
Is this phosphoferrite?
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 phosphoferrite with a known reference. Phosphoferrite sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Phosphoferrite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Phosphoferrite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white, pale yellow, pale green, bluish.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: prismatic crystals, granular aggregates, drusy crusts.
Often confused with
Phosphoferrite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside phosphoferrite
Minerals reported to co-occur with phosphoferrite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe²⁺₃(PO₄)₂·3H₂O
- Mohs hardness
- 3-4
- Density
- 3.55-3.61 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Prismatic Crystals, Granular Aggregates, Drusy Crusts
- Cleavage
- Good On {100}, Poor On {010}
- Rarity
- Rare
- Uses
- Collector, Scientific Research
- Host rock
- Granite Pegmatites
- Typical price
- $20-150 for thumbnail to miniature specimens
Where rockhounds find phosphoferrite
Classic worldwide localities
- Hagendorf, Bavaria, Germany
- Palermo Mine, New Hampshire, USA
- Bull Moose Mine, South Dakota, USA
- Mangualde, Portugal
Field-hunting tip
Look in granite pegmatites country — that is the host setting where phosphoferrite typically forms. If you start seeing triphylite, vivianite, ludlamite in float, you are in the right ground. Field specimens usually show a prismatic crystals, granular aggregates, drusy crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify phosphoferrite?+
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What rocks look like phosphoferrite?+
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Find phosphoferrite on the map
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