Tsepinite-Sr is a rare member of the labuntsovite group typically found in alkaline igneous pegmatites. It forms small, prismatic to acicular crystals often grouped in radial or fan-like aggregates, and is primarily sought by advanced mineral collectors of complex silicates.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent to translucent

mineralrareLabuntsovite Group family

Tsepinite-Sr

Hardness: 5
Luster: Vitreous
Streak: White
Transparency: Transparent to translucent

No image

Is this tsepinite-sr?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch tsepinite-sr with a known reference. Tsepinite-Sr sits at Mohs 5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: colorless, white.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: prismatic crystals, radial aggregates.

Often confused with

Tsepinite-Sr vs. its common look-alikes, and how to tell them apart in the field.

mineral

Labuntsovite

Mohs 6

How to tell apart: Labuntsovite is the harder of the two (Mohs 6 vs. 5); luster reads vitreous on Tsepinite-Sr and greasy on Labuntsovite.

Often found alongside tsepinite-sr

Minerals reported to co-occur with tsepinite-sr. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: (Sr,Ba,K)(Ti,Nb)₂Si₄O₁₂(OH,O)₂·3H₂O
Mohs hardness: 5
Density: 2.67 g/cm³
Colors: Colorless White
Streak: White
Luster: Vitreous
Transparency: Transparent to translucent
Crystal system: Monoclinic
Crystal habit: Prismatic crystals, radial aggregates
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: In cavities formed by hydrothermal alteration of nepheline-syenite pegmatite

Where rockhounds find tsepinite-sr

Classic worldwide localities

Mt. Eveslogchorr and Mt. Khibinpakhkchorr, Khibiny alkaline massif, and Mt. Lepkhe-Nel'm, Lovozero massif, Kola Peninsula, Russia

Field-hunting tip

Where it forms: In cavities formed by hydrothermal alteration of nepheline-syenite pegmatite. If you start seeing microcline, albite, natrolite in float, you are in the right ground. Typical habit: prismatic crystals, radial aggregates. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify tsepinite-sr?+

Mohs hardness is 5. Luster: vitreous. The streak is white. Common colors include colorless, white.

Where is tsepinite-sr found?+

Notable localities include Mt. Eveslogchorr and Mt. Khibinpakhkchorr, Khibiny alkaline massif, and Mt. Lepkhe-Nel'm, Lovozero massif, Kola Peninsula, Russia.

What rocks look like tsepinite-sr?+

Tsepinite-Sr is most often confused with Labuntsovite, Nenadkevichite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with tsepinite-sr?+

Tsepinite-Sr commonly co-occurs with Microcline, Albite, Natrolite, Analcime, Aegirine, Eudialyte. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does tsepinite-sr form in?+

Where it forms: In cavities formed by hydrothermal alteration of nepheline-syenite pegmatite. Working float back to the host body is the standard way to chase a fresh occurrence.

What is tsepinite-sr used for?+

Tsepinite-Sr is used in collector.

Find tsepinite-sr on the map

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