Tsepinite-K is a rare member of the labuntsovite group found primarily in hyper-alkaline pegmatite complexes. It typically occurs as small prismatic or tabular crystals within cavities, often associated with other rare alkaline minerals like aegirine and eudialyte. Collectors prize it for its association with the unique mineralogy of the Kola Peninsula.
Is this tsepinite-k?
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 tsepinite-k with a known reference. Tsepinite-K 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: vitreous.
- 4Match the color rangeCompare against the expected color range: light brown, white, colorless.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic.
Often confused with
Tsepinite-K vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Labuntsovite is the harder of the two (Mohs 6 vs. 5); luster reads vitreous on Tsepinite-K and greasy on Labuntsovite.
How to tell apart: Streak differs, so Tsepinite-K leaves white, Nekrasovite leaves black; luster reads vitreous on Tsepinite-K and metallic on Nekrasovite.
Often found alongside tsepinite-k
Minerals reported to co-occur with tsepinite-k. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (K,Ba,Na)₂(Ti,Nb)₂Si₄O₁₂(OH,O)₂·3H₂O
- Mohs hardness
- 5
- Density
- 2.88 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic
- Cleavage
- Imperfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In cavities formed by hydrothermal alteration of alkaline pegmatite
Where rockhounds find tsepinite-k
Classic worldwide localities
- Mt. Kukisvumchorr and Mt. Eveslogchorr, Khibiny alkaline complex, and Mt. Karnasurt, Lovozero alkaline massif, Kola Peninsula, Russia
Field-hunting tip
Where it forms: In cavities formed by hydrothermal alteration of alkaline pegmatite. If you start seeing aegirine, manganneptunite, natrolite in float, you are in the right ground. Typical habit: prismatic. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify tsepinite-k?+
Where is tsepinite-k found?+
What rocks look like tsepinite-k?+
What minerals are found with tsepinite-k?+
What kind of rock does tsepinite-k form in?+
What is tsepinite-k used for?+
Find tsepinite-k on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
