Kribergite is an extremely rare aluminum phosphate mineral found primarily in Swedish phosphate deposits. It typically forms as tiny, delicate tabular crystals or crusts that require a loupe or microscope for proper identification.
Is this kribergite?
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 kribergite with a known reference. Kribergite 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: white.
- 3Read the lusterHold the specimen under a strong light. Luster: dull.
- 4Match the color rangeCompare against the expected color range: white.
- 5Look at form & habitCrystal system: triclinic. Typical habit: tabular crystals.
Often confused with
Kribergite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads dull on Kribergite and vitreous to resinous, pearly on Wavellite.
How to tell apart: Variscite is the harder of the two (Mohs 4.5 vs. 3.5); luster reads dull on Kribergite and vitreous to waxy on Variscite.
Often found alongside kribergite
Minerals reported to co-occur with kribergite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Al₅(PO₄)₃(SO₄)(OH)₄·4H₂O
- Mohs hardness
- 3.5
- Density
- 1.92 g/cm³
- Colors
- Streak
- White
- Luster
- Dull
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Tabular crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Filling fractures in cupriferous pyrite
Where rockhounds find kribergite
Classic worldwide localities
- Kristineberg mine, Viisterbotten, Sweden
Field-hunting tip
Where it forms: Filling fractures in cupriferous pyrite. If you start seeing pyrite in float, you are in the right ground. Typical habit: tabular crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify kribergite?+
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What rocks look like kribergite?+
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Find kribergite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
