Allanpringite is a rare hydrated iron phosphate mineral that typically forms as delicate, radiating needles or sprays. Collectors usually find it as a secondary mineral in the weathered zones of phosphate-rich granite pegmatites associated with other iron phosphates.
Is this allanpringite?
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 allanpringite with a known reference. Allanpringite 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. Streak: pale yellowish white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: pale brownish yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: acicular.
Often confused with
Allanpringite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Allanpringite leaves pale yellowish white, Santabarbaraite leaves amber.
How to tell apart: Allanpringite is noticeably harder (Mohs 3 vs. 1.5-2); streak differs, so Allanpringite leaves pale yellowish white, Vivianite leaves white, altering to dark blue, brown.
Often found alongside allanpringite
Minerals reported to co-occur with allanpringite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe³⁺₃(PO₄)₂(OH)₃·5H₂O
- Mohs hardness
- 3
- Density
- 2.54 g/cm³
- Colors
- Pale brownish yellow
- Streak
- Pale yellowish white
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Acicular
- Cleavage
- Perfect on {hk0}; good on {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Secondary mineral on dump of the abandoned mine
Where rockhounds find allanpringite
Classic worldwide localities
- Grube Mark near Essershausen, Taunus, Hesse, Germany (type locality)
Field-hunting tip
Where it forms: Secondary mineral on dump of the abandoned mine. If you start seeing strengite, leucophosphite, rockbridgeite in float, you are in the right ground. Typical habit: acicular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify allanpringite?+
Where is allanpringite found?+
What rocks look like allanpringite?+
What minerals are found with allanpringite?+
What kind of rock does allanpringite form in?+
What is allanpringite used for?+
Find allanpringite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
