Kalifersite is a very rare silicate mineral typically found in the vugs of alkaline pegmatites. Collectors look for its delicate, needle-like acicular crystals which often form radiating sprays within small cavities.
Is this kalifersite?
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 kalifersite with a known reference. Kalifersite 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. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: earthy to silky.
- 4Match the color rangeCompare against the expected color range: brownish pink.
- 5Look at form & habitCrystal system: triclinic. Typical habit: fibrous.
Often confused with
Kalifersite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside kalifersite
Minerals reported to co-occur with kalifersite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K₅Fe₇Si₂₀O₅₀(OH)₆·12H₂O
- Mohs hardness
- 2
- Density
- 2.37 g/cm³
- Colors
- Brownish pink
- Streak
- White
- Luster
- Earthy to silky
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Fibrous
- Cleavage
- Good on {100} and {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In hydrothermally altered peralkaline pegmatite in urtite
Where rockhounds find kalifersite
Classic worldwide localities
- Mt. Kukisvumchorr, Khibina massif, Kola Peninsula, Russia
Field-hunting tip
Where it forms: In hydrothermally altered peralkaline pegmatite in urtite. If you start seeing aegirine, fenaksite, pectolite in float, you are in the right ground. Typical habit: fibrous. Train your eye for that shape before scanning the outcrop.





