Polylithionite is a lithium-rich mica typically found in silica-undersaturated alkaline rocks and pegmatites. It often forms thin, platy, or tabular crystals that exhibit the classic perfect basal cleavage of the mica group, though it is usually identified by its association with rare alkaline minerals like Eudialyte.

Hardness

2.5-3

Mohs

Luster

Pearly

Streak

White

Transparency

Transparent

mineraluncommonMica Group family

Polylithionite

Hardness: 2.5-3
Luster: Pearly
Streak: White
Transparency: Transparent

Is this polylithionite?

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 polylithionite with a known reference. Polylithionite sits at Mohs 2.5-3 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Polylithionite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Polylithionite typically shows a pearly luster.
4
Match the color range
Compare against the expected color range: colorless, white, pale pink, pale green.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: tabular crystals, micaceous sheets, scaly aggregates.

Often confused with

Polylithionite vs. its common look-alikes — and how to tell them apart in the field.

Often found alongside polylithionite

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

All properties

Chemical formula: KLi₂AlSi₄O₁₀(F,OH)₂
Mohs hardness: 2.5-3
Density: 2.8-2.9 g/cm³
Colors: Colorless White Pale Pink Pale Green
Streak: White
Luster: Pearly
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Tabular Crystals, Micaceous Sheets, Scaly Aggregates
Cleavage: Perfect Basal
Rarity: Uncommon
Uses: Collector, Scientific Research
Host rock: Alkaline Igneous Rocks, Pegmatites
Typical price: $10-60 per specimen

Where rockhounds find polylithionite

Classic worldwide localities

Narsarsuk, Greenland
Mont Saint-Hilaire, Canada
Kola Peninsula, Russia
Kvanefjeld, Greenland

Field-hunting tip

Look in alkaline igneous rocks, pegmatites country — that is the host setting where polylithionite typically forms. If you start seeing aegirine, microcline, sodalite in float, you are in the right ground. Field specimens usually show a tabular crystals, micaceous sheets, scaly aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify polylithionite?+

Mohs hardness is 2.5-3. It typically shows a pearly luster. The streak is white. Common colors include colorless, white, pale pink, pale green.

Where is polylithionite found?+

Notable localities include Narsarsuk, Greenland; Mont Saint-Hilaire, Canada; Kola Peninsula, Russia; Kvanefjeld, Greenland.

How much is polylithionite worth?+

Typical asking prices fall in the range of $10-60 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like polylithionite?+

Polylithionite is most often confused with Muscovite, Lepidolite, Phlogopite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with polylithionite?+

Polylithionite commonly co-occurs with Aegirine, Microcline, Sodalite, Zircon, Eudialyte. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does polylithionite form in?+

Polylithionite typically forms in alkaline igneous rocks, pegmatites. Working float back to the host body is the standard way to chase a fresh occurrence.

What is polylithionite used for?+

Polylithionite is used in collector, scientific research.

Find polylithionite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.