Alexkuznetsovite-(La)

Chemical formula: La<sub>2</sub>Mn<sup>2+</sup>(CO<sub>3</sub>)(Si<sub>2</sub>O<sub>7</sub>)

A rare lanthanum and manganese silicate-carbonate, forming small, acicular yellow crystals in a pyrometamorphic paragenesis.

## Characteristics Alexkuznetsovite-(La) is a complex mineral from the silicate and carbonate groups, containing lanthanum and manganese. It occurs as very small, prismatic or acicular crystals, not exceeding 0.2 mm in length. These crystals often form radial aggregates. The mineral is characterized by a vitreous luster and is transparent. ## Physical Properties The mineral is transparent, with a vitreous luster. Its density, calculated from the chemical formula and unit cell parameters, is 4.61 g/cm³. The Mohs hardness has not yet been determined. There is also no data on cleavage or fracture. ## Colors and Varieties Alexkuznetsovite-(La) ranges in color from pale yellow to yellowish-brown. No color varieties or commercial varieties have been distinguished. ## History and Name The mineral was officially recognized by the International Mineralogical Association (IMA) in 2020 (IMA number 2020-061). Its name honors Aleksey M. Kuznetsov (born 1960), a Russian collector and specialist in minerals formed in burning coal dumps in the Chelyabinsk Coal Basin. The suffix "-(La)" indicates that lanthanum is the dominant rare earth element in this mineral, according to Levinson's nomenclature rules. ## Applications Due to its extreme rarity and microscopic size, alexkuznetsovite-(La) has no industrial applications. It serves solely as an object of scientific research and a valuable acquisition for specialized micromineral collectors.

Properties

Luster
Vitreous
Streak
White
Density
4.61
Transparency
Transparent
Crystal system
Monoclinic

Diagnostic features

## Identification Amateur identification of the mineral is practically impossible. Key indicators include: a unique occurrence environment (burning coal dump), paragenesis with other pyrometamorphic minerals, and the characteristic form of small, acicular yellow crystals. Final confirmation of identity requires advanced analytical methods, such as X-ray diffraction (XRD) and chemical microanalysis (EDS/WDS). ## Distinguishing from Similar Minerals Alexkuznetsovite-(La) is visually indistinguishable from many other yellow, acicular microminerals without specialized examination. Its unique chemical composition, combining silicate (Si₂O₇) and carbonate (CO₃) groups with lanthanum and manganese, is a definitive characteristic. ## Crystal Forms The mineral forms crystals with a prismatic to acicular habit. They often occur as radial aggregates, radiating from a single center.

Geological environment

## Genesis Alexkuznetsovite-(La) is a product of pyrometamorphic processes. It forms as a result of secondary, high-temperature alterations occurring within burning coal dumps, where specific reducing conditions and high temperatures prevail. ## Mineral Associations This mineral co-occurs with other products of pyrometamorphism, such as anhydrite, hematite, melilite group minerals, kalsilite, diopside, orthoclase, fluorapatite, magnesioferrite, and ellestadite. ## Localities The only confirmed occurrence of this mineral in the world is its type locality – a burning dump at the "Krasnogorsky" coal quarry near Kopeysk, in the Chelyabinsk Coal Basin, Russia.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of collector specimens of this micromineral is assessed based on several criteria. Specimens with well-formed, sharp, and undamaged crystals are most desirable. Rich aggregates and radial groupings are also highly valued. The value of a specimen is enhanced by an aesthetic composition with other, color-contrasting associated minerals on the rock matrix. ## Popular Localities The only source of alexkuznetsovite-(La) specimens is its type locality in Russia. Material from this location is extremely limited and primarily available through specialized channels.

Care and storage

## Cleaning Specimens should only be cleaned dry, using a soft brush or compressed air to remove dust. Contact with water and other liquids is not recommended. ## What to Avoid Avoid contact with all chemicals, especially acids, which can react with the carbonate group in the mineral's structure. Cleaning in ultrasonic cleaners, heating, and exposure to sudden temperature changes are not recommended. Due to the small size of the crystals, specimens are very susceptible to mechanical damage. ## Storage It is recommended to store specimens in closed, stable "perky box" containers, protecting them from dust, moisture, and damage. Each specimen should be properly labeled, including its locality.

Sources

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