Lepageite is an extremely rare phosphate mineral discovered in complex granite pegmatites. It typically occurs as small, platy, yellowish-brown crystals often found as an alteration product of triphylite.
Is this lepageite?
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 lepageite with a known reference. Lepageite sits at Mohs 2 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Lepageite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Lepageite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellow-brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy crystals.
Often confused with
Lepageite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Hureaulite is the harder of the two (Mohs 3.5 vs. 2); luster reads pearly on Lepageite and vitreous on Hureaulite.
How to tell apart: Phosphosiderite is the harder of the two (Mohs 3.5-4 vs. 2); luster reads pearly on Lepageite and vitreous on Phosphosiderite.
Often found alongside lepageite
Minerals reported to co-occur with lepageite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂Mn₄(Fe³⁺,Mn³⁺)₂(PO₄)₄(OH)₂·11H₂O
- Mohs hardness
- 2
- Density
- 2.53 g/cm³
- Colors
- Streak
- White
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Platy Crystals
- Cleavage
- Perfect On {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Granite Pegmatites
- Typical price
- $50-300 per specimen
Where rockhounds find lepageite
Classic worldwide localities
- Tip Top mine, Custer County, South Dakota, USA
Field-hunting tip
Look in granite pegmatites country — that is the host setting where lepageite typically forms. If you start seeing hureaulite, triphylite, eosphorite in float, you are in the right ground. Field specimens usually show a platy crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find lepageite on the map
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