Kalborsite is a rare phyllosilicate mineral found primarily in alkaline pegmatites and nepheline syenites. Collectors look for its characteristic tetragonal prismatic crystals that often form in tight associations with other rare-earth minerals in the Kola Peninsula regions.
Is this kalborsite?
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 kalborsite with a known reference. Kalborsite sits at Mohs ~6, 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: vitreous to pearly on cleavages.
- 4Match the color rangeCompare against the expected color range: brownish pink, colorless.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: epitaxial.
Often confused with
Kalborsite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside kalborsite
Minerals reported to co-occur with kalborsite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K₆BAl₄Si₆O₂₀Cl(OH)₄
- Mohs hardness
- ~6
- Density
- 2.5 g/cm³
- Colors
- Brownish pinkColorless
- Streak
- White
- Luster
- Vitreous to pearly on cleavages
- Transparency
- Translucent to transparent
- Crystal system
- Tetragonal
- Crystal habit
- Epitaxial
- Cleavage
- Perfect on {110}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Forms rims around lovozerite in segregations of pectolite, in rischorrite pegmatite from a differentiated alkalic massif
Where rockhounds find kalborsite
Classic worldwide localities
- Mt. Rasvumchorr, Khibiny massif, Kola Peninsula, Russia
Field-hunting tip
Where it forms: Forms rims around lovozerite in segregations of pectolite, in rischorrite pegmatite from a differentiated alkalic massif. If you start seeing pectolite, lovozerite in float, you are in the right ground. Typical habit: epitaxial. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify kalborsite?+
Where is kalborsite found?+
What rocks look like kalborsite?+
What minerals are found with kalborsite?+
What kind of rock does kalborsite form in?+
What is kalborsite used for?+
Find kalborsite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
