Alexkuznetsovite-(Ce)

Chemical formula: Ce₃+₂Mn₂+(CO₃)(Si₂O₇)

An extremely rare sorosilicate and carbonate of cerium and manganese, forming microscopic, acicular, brownish crystals.

## Characteristics Alexkuznetsovit-(Ce) is a complex mineral from the silicate group, combining cerium ions, manganese, a carbonate group, and a sorosilicate group (Si₂O₇) in its structure. It occurs as very small, prismatic or acicular crystals, whose length does not exceed 0.2 mm. These crystals often form radial or fan-shaped aggregates. Its color ranges from yellowish-brown to brown. Due to the microscopic size of the crystals, it is a typical "micromineral," requiring magnification for observation. ## Physical Properties The mineral is characterized by a vitreous luster and is translucent. Its density, calculated based on chemical composition and unit cell parameters, is 4.51 g/cm³. The Mohs hardness has not yet been determined. ## Colors and Varieties Observed colors are shades of brown, from yellowish to darker brown. As a newly described and extremely rare mineral, it has no known color varieties or trade names. ## History and Name The mineral was officially approved by the International Mineralogical Association (IMA) in 2020. Its name honors the Russian mineralogist and crystallographer, Dr. Alexey V. Kuznetsov (born 1978), for his contribution to the study of minerals from alkaline massifs. The type locality (locus typicus), i.e., the place of discovery, is the "Shkatulka" pegmatite in the Khibiny Massif on the Kola Peninsula, Russia. ## Applications Due to its extreme rarity and microscopic size, alexkuznetsovit-(Ce) has no industrial applications. It is exclusively an object of scientific research and a valuable acquisition for specialized micromineral collectors.

Properties

Luster: Vitreous
Streak: Light yellow
Density: 4.51
Transparency: Translucent
Crystal system: Monoclinic

Diagnostic features

## Identification Identification based on visual characteristics is practically impossible and very uncertain. Recognition relies on characteristic morphology (radial aggregates of acicular crystals), brown color, and co-occurrence with other rare minerals in Khibiny Massif pegmatites. Certain identification requires advanced analytical methods, such as energy-dispersive spectroscopy (EDS) to determine chemical composition and X-ray diffraction (XRD) to confirm crystal structure. ## Distinguishing from Similar Minerals It can be confused with other brown, acicular minerals found in the same environment, such as some amphiboles, pyroxenes (aegirine), or lorenzenite. Differentiation without chemical analysis is unreliable. ## Crystal Forms It forms elongated, prismatic to acicular crystals. It is most commonly found in the form of radial or fan-shaped aggregates, growing on other minerals.

Geological environment

## Genesis Alexkuznetsovit-(Ce) forms in the late stages of crystallization of highly differentiated alkaline pegmatites, rich in rare earth elements (REE), manganese, and fluorine. It is a product of hydrothermal or metasomatic processes occurring within these pegmatites. ## Mineral Associations At the type locality, it co-occurs with many other minerals, including microcline, albite, aegirine, eudialyte, lorenzenite, fluorapatite, rinkite-(Ce), and other rare REE minerals. ## Localities The only confirmed locality in the world is the "Shkatulka" pegmatite (Russian: Шкатулка), located in the Khibiny Massif on the Kola Peninsula, Murmansk Oblast, Russia.

Rarity

Extremely rare

For collectors

## Quality Criteria For this micromineral, specimens with well-formed, sharp crystals forming aesthetic, radial aggregates are most highly valued. Contrast with the matrix mineral and the presence of other rare associated minerals are also important. ## Market Prices There is no established market for this mineral. Specimens are mainly found in institutional collections and are exchanged among specialized collectors. ## Popular Localities The only source of specimens is its type locality - the "Shkatulka" pegmatite in Russia.

Care and storage

## Cleaning Specimens should only be cleaned with compressed air to remove dust. Due to the fragility and small size of the crystals, mechanical cleaning (brushes) and contact with water and chemicals are not recommended. ## What to Avoid Avoid ultrasound, all chemical solvents, acids, and sudden temperature changes. The crystals are very fragile and susceptible to mechanical damage. ## Storage The safest way to store specimens is to place them in a sealed "micromount" box, which protects them from dust, shocks, and contact with other minerals.

Sources

IMA Mineral List (CNMNC)