Beraunite is a secondary phosphate mineral typically forming in the weathered oxidation zones of iron ore deposits. Collectors most commonly encounter it as striking radial clusters or botryoidal crusts of deep red-brown crystals often associated with other rare phosphates.
Is this beraunite?
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 beraunite with a known reference. Beraunite 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. Streak: olive-drab when fresh; yellow, brownish yellow on exposure.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous, pearly on cleavages, resinous on fractures.
- 4Match the color rangeCompare against the expected color range: green, greenish brown, gray green, dark greenish brown, dark red.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: druse, globular, radial.
Often confused with
Beraunite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Beraunite leaves olive-drab when fresh; yellow, brownish yellow on exposure, Dufrénite leaves green.
How to tell apart: Streak differs, so Beraunite leaves olive-drab when fresh; yellow, brownish yellow on exposure, Strengite leaves white.
How to tell apart: Beraunite is noticeably harder (Mohs 3-4 vs. 1.5-2); streak differs, so Beraunite leaves olive-drab when fresh; yellow, brownish yellow on exposure, Vivianite leaves white, altering to dark blue, brown.
Often found alongside beraunite
Minerals reported to co-occur with beraunite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe₆(PO₄)₄O(OH)₄·6H₂O
- Mohs hardness
- 3-4
- Density
- 2.8-3.08 g/cm³
- Colors
- Streak
- Olive-drab when fresh; yellow, brownish yellow on exposure
- Luster
- Vitreous, pearly on cleavages, resinous on fractures
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Druse, globular, radial
- Cleavage
- On {100}, good
- Rarity
- Uncommon
- Uses
- Collector
- Host rock
- A component of bog iron ores; a cement in clays, sands, and bone material; an alteration product of triphylite in granite pegmatites
Where rockhounds find beraunite
Classic worldwide localities
- Palermo #1 and Fletcher mines, near North Groton, Grafton Co., New Hampshire, USA
- Raccoon Creek, Mullica Hill, Gloucester Co., New Jersey, USA
- Hesnard mine, three km southwest of Keystone, and the Big Chief mine, one km south of Glendale, Pennington Co., South Dakota, USA
- Foote mine, near Kings Mountain, Cleveland Co., North Carolina, USA
- Hrbek mine, at St. Benigna, near Beroun, Czech Republic
- Eleonore and Rotläufchen iron mines, near Giessen, Hesse, Germany
Field-hunting tip
Where it forms: A component of bog iron ores; a cement in clays, sands, and bone material; an alteration product of triphylite in granite pegmatites. If you start seeing vivianite, dufrénite, rockbridgeite in float, you are in the right ground. Typical habit: druse, globular, radial. Train your eye for that shape before scanning the outcrop.
Common questions
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Find beraunite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
