Selivanovaite

Chemical formula: Fe³⁺◻Ti⁴⁺₂Na◻Ti⁴⁺₂(Si₂O₇)₂O₄(H₂O)₄

Seliwanowite is an extremely rare mineral from the silicate group, found as microscopic, platy crystals of a brown color.

## Characteristics Seliwanowite is a very rare sodium, iron, and titanium silicate, belonging to the murmanite group. It occurs as extremely small, thin, platy crystals, reaching sizes up to 0.2 x 0.1 x 0.01 mm. These crystals often form radial or chaotic aggregates. Due to its microscopic size, its visual characteristics are difficult to observe without specialized equipment. ## Physical Properties Seliwanowite crystals exhibit a vitreous luster. They are brittle, and their hardness and density have not been precisely measured due to the small size of the samples. ## Colors and Varieties This mineral is light brown to reddish-brown in color. It has no known varieties. ## History and Name Seliwanowite was discovered in material from the Lovozero Massif on the Kola Peninsula in Russia. It was approved as a new mineral species by the International Mineralogical Association (IMA) in 2021. Its name honors the Russian geologist and mineralogist Yulia Vyacheslavovna Selivanova (born 1985), in recognition of her contributions to the study of the mineralogy of alkaline massifs, including the Lovozero Massif.

Properties

Mohs hardness
3
Color
Dark-orange
Luster
Vitreous
Streak
Brownish-white
Density
3.15
Cleavage
Perfect on {001} and weak on {110}.
Fracture
Step-Like
Transparency
Translucent
Crystal system
Triclinic

Diagnostic features

## Identification Identification of seliwanowite is possible only through advanced analytical methods, such as Raman spectroscopy and chemical analysis using an electron microprobe (EDS/WDS). Visual identification in the field or in a collection is impossible. ## Distinguishing from Similar Minerals Seliwanowite is morphologically similar to other minerals of the murmanite group, such as murmanite, epistolite, and lomonosovite. Differentiation requires specialized analysis of chemical composition, especially iron and titanium content. ## Crystal Forms It forms very small, thin, bladed or platy crystals, often grouped into radial aggregates.

Geological environment

## Genesis Seliwanowite forms in the late stages of hydrothermal processes in ultra-agpaitic pegmatites, associated with alkaline massifs. It crystallizes in rock cavities and fissures. ## Mineral Associations This mineral coexists with other rare alkaline minerals, such as vuonnemite, lomonosovite, sodalite, eudialyte, lamprophyllite, as well as new, yet unnamed mineral phases. ## Localities The only confirmed occurrence of seliwanowite in the world is its type locality – Mount Alluaiv in the Lovozero Massif on the Kola Peninsula in Russia.

Rarity

Extremely rare

For collectors

## Quality Criteria As a "micromount" mineral, the collector's value of seliwanowite depends on the abundance of crystal aggregates on the rock matrix and on the quality and size of individual crystals, visible under a microscope. Association with other rare minerals is also important. ## Popular Localities The only source of specimens is the Lovozero Massif in Russia. These specimens are extremely difficult to obtain and are almost exclusively found in institutional collections and specialized micromineral collectors.

Care and storage

## Cleaning Due to the extreme rarity and microscopic size of crystals embedded in the host rock, seliwanowite specimens should not be cleaned mechanically or chemically. Any attempt at cleaning risks irreversible destruction of the mineral. ## What to Avoid Avoid contact with chemicals, ultrasound, and any tools. Specimens should be protected from dust, moisture, and sudden temperature changes. ## Storage Seliwanowite specimens should be stored exclusively in specialized "micromount" boxes, protecting them from physical damage and contamination. Display is only possible under a microscope.

External references

Sources

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