Frankamenite is a rare silicate mineral primarily found in alkaline igneous complexes, occurring most notably in the Murun Massif of Russia. It typically appears as fibrous to acicular prismatic crystals that often exhibit a pale blue to white coloration.
Is this frankamenite?
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 frankamenite with a known reference. Frankamenite sits at Mohs 5-6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Frankamenite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Frankamenite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, pale blue, pale yellow.
- 5Look at form & habitCrystal system: triclinic. Typical habit: fibrous, acicular, prismatic.
Often confused with
Frankamenite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside frankamenite
Minerals reported to co-occur with frankamenite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K₃Na₃Ca₅Si₁₂O₃₀(OH,F)₂·H₂O
- Mohs hardness
- 5-6
- Density
- 2.71 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Fibrous, Acicular, Prismatic
- Cleavage
- Perfect On {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alkaline Igneous Pegmatites
- Typical price
- $50-300 per specimen
Where rockhounds find frankamenite
Classic worldwide localities
- Khibiny Massif, Kola Peninsula, Russia
- Murun Massif, Yakutia, Russia
Field-hunting tip
Look in alkaline igneous pegmatites country — that is the host setting where frankamenite typically forms. If you start seeing kalsilite, potassian feldspar, aegirine in float, you are in the right ground. Field specimens usually show a fibrous, acicular, prismatic habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find frankamenite on the map
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