Bermanite is a secondary phosphate mineral typically found in granite pegmatites as an alteration product of triphylite. Collectors look for its distinctive reddish-brown tabular crystals that often form radiating groups or thin crusts in weathered pockets.
Is this bermanite?
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 bermanite with a known reference. Bermanite sits at Mohs 3.5, 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 to slightly resinous, dull.
- 4Match the color rangeCompare against the expected color range: light red, dark reddish brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, platy aggregates, crusts.
Often confused with
Bermanite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Triplite is the harder of the two (Mohs 5-5.5 vs. 3.5); streak differs, so Bermanite leaves pale yellow, Triplite leaves white to brown.
How to tell apart: Streak differs, so Bermanite leaves pale yellow, Fairfieldite leaves white; luster reads vitreous to slightly resinous, dull on Bermanite and pearly to subadamantine, vitreous on the {001} cleavage on Fairfieldite.
Often found alongside bermanite
Minerals reported to co-occur with bermanite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mn²⁺Mn³⁺₂(PO₄)₂(OH)₂·4H₂O
- Mohs hardness
- 3.5
- Density
- 2.84-2.85 g/cm³
- Streak
- Pale yellow
- Luster
- Vitreous to slightly resinous, dull
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular crystals, platy aggregates, crusts
- Cleavage
- Perfect on {001}; imperfect on {110}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A late-stage hydrothermal mineral replacing primary phosphate phases, usually triplite or lithiophilite, in complex granite pegmatites
Where rockhounds find bermanite
Classic worldwide localities
- Williams pegmatite, Coosa Co., Alabama, USA
- Stewart Lithia mine, Pala, San Diego Co., California, USA
- White Elephant, Bull Moose, Linwood, and Tip Top mines, near Custer, Custer Co., South Dakota, USA
- Palermo #1 and Fletcher mines, near North Groton, Grafton Co., New Hampshire, USA
- El Criollo pegmatite, Cerro Blanco, Tanti district, 45 km west of Córdoba, Córdoba Province, Argentina
- McMahon quarry, near Olary, and in the Wiperaminga Hill West quarry, Boolcoomata, South Australia
Field-hunting tip
Where it forms: A late-stage hydrothermal mineral replacing primary phosphate phases, usually triplite or lithiophilite, in complex granite pegmatites. If you start seeing triplite, strengite, leucophosphite in float, you are in the right ground. Typical habit: tabular crystals, platy aggregates, crusts. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify bermanite?+
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What rocks look like bermanite?+
What minerals are found with bermanite?+
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Find bermanite on the map
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