Lomonosovite is a complex sodium titanium phosphate silicate primarily found in rare alkaline intrusive complexes. It typically presents as brown to reddish-brown tabular or platy crystals that are prone to alteration into murmanite when exposed to hydrous conditions.

Hardness

3-4

Mohs

Luster

Vitreous to adamantine on cleavages, greasy on fractures

Streak

Light rose-cinnamon

Transparency

Transparent in thin plates

mineralrareLomonosovite Group family

Lomonosovite

Hardness: 3-4
Luster: Vitreous to adamantine on cleavages, greasy on fractures
Streak: Light rose-cinnamon
Transparency: Transparent in thin plates

Is this lomonosovite?

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 lomonosovite with a known reference. Lomonosovite sits at Mohs 3-4, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: light rose-cinnamon.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous to adamantine on cleavages, greasy on fractures.
4
Match the color range
Compare against the expected color range: dark brown, pink violet, black.
5
Look at form & habit
Crystal system: triclinic. Typical habit: tabular.

Often confused with

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

mineral

Murmanite

Mohs 2-3

How to tell apart: Streak differs, so Lomonosovite leaves light rose-cinnamon, Murmanite leaves white.

How to tell apart: Streak differs, so Lomonosovite leaves light rose-cinnamon, Seidozerite leaves yellow-brown.

Compare →

Often found alongside lomonosovite

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

All properties

Chemical formula: Na₅Ti₂Si₂O₉(PO₄)
Mohs hardness: 3-4
Density: 2.88-3.13 g/cm³
Colors: Dark brownPink violetBlack
Streak: Light rose-cinnamon
Luster: Vitreous to adamantine on cleavages, greasy on fractures
Transparency: Transparent in thin plates
Crystal system: Triclinic
Crystal habit: Tabular
Cleavage: Perfect on {100}
Rarity: Rare
Uses: Collector
Host rock: alkaline igneous rocks

Where rockhounds find lomonosovite

Classic worldwide localities

Lovozero alkaline complex, Kola Peninsula, Russia (type locality)

Field-hunting tip

Where it forms: alkaline igneous rocks. If you start seeing nepheline, albite, pectolite in float, you are in the right ground. Typical habit: tabular. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify lomonosovite?+

Mohs hardness is 3-4. Luster: vitreous to adamantine on cleavages, greasy on fractures. The streak is light rose-cinnamon. Common colors include dark brown, pink violet, black.

Where is lomonosovite found?+

Notable localities include Lovozero alkaline complex, Kola Peninsula, Russia (type locality).

What rocks look like lomonosovite?+

Lomonosovite is most often confused with Murmanite, Seidozerite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with lomonosovite?+

Lomonosovite commonly co-occurs with Nepheline, Albite, Pectolite, Lorenzenite, Ussingite, Lamprophyllite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does lomonosovite form in?+

Where it forms: alkaline igneous rocks. Working float back to the host body is the standard way to chase a fresh occurrence.

What is lomonosovite used for?+

Lomonosovite is used in collector.

Find lomonosovite on the map

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