Chirvinskyite is an extremely rare silicate mineral typically found as small, thin tabular crystals in alkaline pegmatite environments. Collectors primarily find it as a microscopic or thumbnail specimen associated with other rare-earth bearing minerals from the Khibiny Massif. Identification usually requires professional analysis or XRD due to its superficial resemblance to other complex sheet silicates in the region.
Is this chirvinskyite?
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 chirvinskyite with a known reference. Chirvinskyite sits at Mohs 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: silky.
- 4Match the color rangeCompare against the expected color range: pale cream.
- 5Look at form & habitCrystal system: triclinic. Typical habit: tabular crystals.
Often confused with
Chirvinskyite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Chirvinskyite is noticeably harder (Mohs 5 vs. 3); streak differs, so Chirvinskyite leaves white, Astrophyllite leaves golden; luster reads silky on Chirvinskyite and submetallic, pearly, greasy on Astrophyllite.
How to tell apart: Chirvinskyite is noticeably harder (Mohs 5 vs. 3-4); streak differs, so Chirvinskyite leaves white, Kupletskite leaves brown; luster reads silky on Chirvinskyite and vitreous on Kupletskite.
Often found alongside chirvinskyite
Minerals reported to co-occur with chirvinskyite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Na,Ca)₁₃(Fe,Mn,□)₂Ti₂(Zr,Ti)₃(Si₂O₇)₄(OH,O,F)₁₂
- Mohs hardness
- 5
- Density
- 3.07 g/cm³
- Colors
- Pale cream
- Streak
- White
- Luster
- Silky
- Transparency
- Transparent to translucent
- Crystal system
- Triclinic
- Crystal habit
- Tabular crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In albitized alkaline pegmatites in a foyaite
Where rockhounds find chirvinskyite
Classic worldwide localities
- Mt. Takhtarvumchorr, Khibiny alkaline massif, Kola Peninsula, Russia
Field-hunting tip
Where it forms: In albitized alkaline pegmatites in a foyaite. If you start seeing natrolite, albite, fluorapatite in float, you are in the right ground. Typical habit: tabular crystals. Train your eye for that shape before scanning the outcrop.
Common questions
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Find chirvinskyite on the map
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