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, so Lomonosovite leaves yellowish brown, Murmanite leaves white; luster reads vitreous on Lomonosovite and pearly on Murmanite.
How to tell apart: Streak differs, so 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, 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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