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, 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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