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.
Is this lomonosovite?
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 lomonosovite with a known reference. Lomonosovite sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Lomonosovite leaves a yellowish brown streak.
- 3Read the lusterHold the specimen under a strong light. Lomonosovite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: brown, dark brown, reddish brown, black.
- 5Look at form & habitCrystal system: triclinic. Typical habit: tabular crystals, platy, lamellar aggregates.
Often confused with
Lomonosovite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Lomonosovite leaves yellowish brown, Murmanite leaves white; luster reads vitreous on Lomonosovite and pearly on Murmanite.
How to tell apart: Streak differs — Lomonosovite leaves yellowish brown, Seidozerite leaves yellow-brown.
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
- 3.17 g/cm³
- Streak
- Yellowish Brown
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Tabular Crystals, Platy, Lamellar Aggregates
- Cleavage
- Perfect On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alkaline Igneous Rocks
- Typical price
- $50-300 per specimen
Where rockhounds find lomonosovite
Classic worldwide localities
- Kola Peninsula, Russia
- Mont Saint-Hilaire, Canada
- Ilímaussaq Complex, Greenland
Field-hunting tip
Look in alkaline igneous rocks country — that is the host setting where lomonosovite typically forms. If you start seeing nepheline, aegirine, microcline in float, you are in the right ground. Field specimens usually show a tabular crystals, platy, lamellar aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify lomonosovite?+
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Find lomonosovite on the map
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