Paralomonosovite
Chemical formula: Na<sub>2</sub>☐<sub>4</sub>Na<sub>2</sub>Ti<sup>4+</sup><sub>2</sub>Na<sub>2</sub>Ti<sup>4+</sup><sub>2</sub>(Si<sub>2</sub>O<sub>7</sub>)<sub>2</sub>[PO<sub>3</sub>(OH)][PO<sub>2</sub>(OH)<sub>2</sub>]O<sub>2</sub>(OF)
Paralomonosovite is a very rare mineral from the silicate group, found as platy crystals in alkaline massifs.
Properties
- Mohs hardness
- 5
- Luster
- Vitreous, Pearly
- Streak
- White
- Density
- 3.16
- Cleavage
- Perfect on {001}
- Fracture
- Uneven
- Transparency
- Transparent to translucent
- Crystal system
- Triclinic
Diagnostic features
## Identification The key diagnostic features are its platy or lamellar crystal habit, brown color, vitreous to pearly luster, and perfect cleavage. The reaction to water (slow decomposition) is a characteristic but destructive feature for the sample. ## Distinguishing from Similar Minerals Paralomonosovite is difficult to distinguish from lomonosovite and murmanite without advanced studies (XRD, EDS). Lomonosovite typically has a lighter, pinkish-brown color. Murmanite, its weathering product, often has a violet or lilac hue and is less transparent. Distinguishing it from other minerals in the group, such as betalomonosovite, requires laboratory analysis. ## Crystal Forms Crystals are platy, flattened parallel to {001}, with a hexagonal or octagonal outline. They occur as single flakes or form radial, fan-shaped, and sometimes spherulitic aggregates.
Geological environment
## Genesis Paralomonosovite is a magmatic mineral, crystallizing in the late stages of ultra-alkaline intrusions, especially in nepheline syenite pegmatites. It forms in an environment rich in sodium, titanium, and phosphorus. ## Mineral Associations It co-occurs with minerals typical of alkaline pegmatites, such as microcline, nepheline, aegirine, eudialyte, lorenzenite, lomonosovite, murmanite, ramsayite, and villiaumite. ## Localities The most important and classic localities for this mineral are in Russia, in the alkaline massifs of the Kola Peninsula. These are primarily the Lovozero Massif (Alluaiv, Karnasurt, Kedykverpakhk mountains) and the Khibiny Massif (Mount Eveslogchorr).
Rarity
Very rare
For collectors
## Quality Criteria The most prized paralomonosovite specimens are those with well-formed, sharp crystals with a distinct platy habit and an intense, brown color. Large, radial aggregates on a contrasting matrix (e.g., with white nepheline or green aegirine) are particularly sought after. Transparency and the absence of weathering signs (alteration to murmanite) are also important.
Care and storage
## Cleaning Specimens should be cleaned exclusively mechanically, using a soft brush to remove dust. Due to its instability in water, contact with water and other liquids must be strictly avoided. ## What to Avoid Paralomonosovite is unstable in contact with water, in which it decomposes, transforming into murmanite. It should be protected from moisture, water, acids, and other chemicals. It should not be heated or subjected to ultrasound. ## Storage Specimens should be stored in a dry place, preferably in an airtight container or display box, to minimize contact with atmospheric moisture. Exposure to direct sunlight should be avoided, although it is not the primary threat.