Lemmleinite-K is a rare mineral belonging to the labuntsovite group, typically found as small, colorless prismatic crystals. It is primarily identified within the alkaline pegmatites of the Khibiny Massif in Russia, often associated with microcline and aegirine.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent to translucent

mineralrareLabuntsovite Group family

Lemmleinite-K

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

Is this lemmleinite-k?

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 lemmleinite-k with a known reference. Lemmleinite-K 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.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: fibrous, pseudo orthorhombic.

Often confused with

Lemmleinite-K 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 Lemmleinite-K and greasy on Labuntsovite.

Often found alongside lemmleinite-k

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

All properties

Chemical formula: Na₄K₈Ti₈(Si₄O₁₂)₄(O,OH)₈·8H₂O
Mohs hardness: 5
Density: 2.80 g/cm³
Colors: Colorless
Streak: White
Luster: Vitreous
Transparency: Transparent to translucent
Crystal system: Monoclinic
Crystal habit: Fibrous, pseudo orthorhombic
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: In ultra-agpaitic pegmatites in apatite-nepheline in an alkaline massif

Where rockhounds find lemmleinite-k

Classic worldwide localities

Mount Koashva, Khibina alkaline massif, Kola Peninsula, Russia

Field-hunting tip

Where it forms: In ultra-agpaitic pegmatites in apatite-nepheline in an alkaline massif. If you start seeing sodalite, natrolite, aegirine in float, you are in the right ground. Typical habit: fibrous, pseudo orthorhombic. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify lemmleinite-k?+

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

Where is lemmleinite-k found?+

Notable localities include Mount Koashva, Khibina alkaline massif, Kola Peninsula, Russia.

What rocks look like lemmleinite-k?+

Lemmleinite-K 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 lemmleinite-k?+

Lemmleinite-K commonly co-occurs with Sodalite, Natrolite, Aegirine, K-feldspar, Pectolite, Alkali amphibole. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does lemmleinite-k form in?+

Where it forms: In ultra-agpaitic pegmatites in apatite-nepheline in an alkaline massif. Working float back to the host body is the standard way to chase a fresh occurrence.

What is lemmleinite-k used for?+

Lemmleinite-K is used in collector.

Find lemmleinite-k on the map

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