Kuzmenkoite-Mn

Chemical formula: K₄Mn₂+₂Ti₄+₈(Si₄O₁₂)₄(OH,O)₈·₁₀-₁₂H₂O

A rare mineral from the silicate group, forming yellowish-brown, tabular crystals in pegmatites and hydrothermal veins.

## Characteristics Kuzmenkoite-Mn is a complex ring silicate from the labuntsovite group, in which manganese is the dominant cation. It forms characteristic thin, tabular or platy crystals, often grouped into radial or spherulitic aggregates. It usually occurs as small, well-formed individuals with a vitreous luster. ## Physical Properties Its Mohs hardness is 5, making it a mineral with medium scratch resistance. The density is approximately 2.86 g/cm³. It is characterized by a vitreous luster, and its crystals can be transparent to translucent. ## Colors and Varieties This mineral ranges in color from yellowish-brown and honey-yellow, through pale yellow, to colorless. No commercial names or color varieties are distinguished. ## History and Name The mineral is named in honor of Viera Markovna Kuzmenko (1909-1984), a Russian mineralogist and geochemist, researcher of the alkaline massifs of the Kola Peninsula. The "-Mn" suffix in the name indicates the dominance of manganese in its chemical composition. The mineral was approved by the International Mineralogical Association (IMA) in 1998. ## Uses Kuzmenkoite-Mn has no industrial applications. However, it is a valued and sought-after collector's mineral due to its rarity, attractive crystal forms, and occurrence in classic, worldwide localities of rare minerals.

Properties

Mohs hardness: 5
Luster: Vitreous
Streak: White
Density: 2.86
Cleavage: Good on {010}
Fracture: Uneven
Transparency: Transparent to translucent
Crystal system: Monoclinic

Diagnostic features

## Identification Kuzmenkoite-Mn can be identified by its characteristic appearance – thin, tabular crystals, often forming radial aggregates. Its color (shades of yellow and brown), vitreous luster, and specific occurrence environment (pegmatites in alkaline massifs) are also helpful. ## Differentiation from similar minerals It can be confused with other minerals from the labuntsovite group, such as labuntsovite-Mn or gutkovaite-Mn. Definitive differentiation requires advanced chemical analysis (e.g., EDS) to determine the proportions of potassium, sodium, and manganese. It is primarily distinguished from other yellow silicates from the same localities by its crystal form. ## Crystal Forms Crystals are thin-tabular or platy, with a pseudohexagonal or rhombic habit. They most often occur as radial or spherulitic aggregates, as well as rosetted clusters on the surface of other minerals.

Geological environment

## Genesis It is a hydrothermal mineral, crystallizing in the late stages of the formation of pegmatites and hydrothermal veins associated with ultra-agpaitic nepheline-syenite massifs. ## Mineral Associations It most often co-occurs with minerals typical of alkaline environments, such as aegirine, natrolite, lorenzenite, eudialyte, vinogradovite, sitinakite, rasvumite, or shcherbakovite. ## Localities The most important and classic occurrences of this mineral are the alkaline massifs on the Kola Peninsula in Russia - Khibiny (Koashva Mountain, Eveslogchorr Mountain) and Lovozero (Karnasurt Mountain, Kedykvyrpakhk Mountain). It is also known from one of the world's most famous rare mineral localities - Mont Saint-Hilaire in Quebec, Canada.

Rarity

Rare

For collectors

## Quality Criteria The most highly valued specimens are those with sharp, well-formed, and transparent crystals of intense, honey-yellow color. The form of aggregates is of great importance – ideal, radial "suns" or rosettes are particularly sought after. The value of a specimen is significantly increased by its placement on an aesthetic rock matrix, especially in the company of other rare minerals. ## Popular Localities Specimens from the Khibiny and Lovozero massifs on the Kola Peninsula and from Mont Saint-Hilaire in Canada are most prized by collectors due to their historical significance and crystal quality.

Care and storage

## Cleaning Specimens should be cleaned very carefully, using a soft brush and distilled water. Ultrasonic cleaners should be avoided as they can damage delicate crystal aggregates. ## What to Avoid The mineral is sensitive to strong acids. As a hydrated mineral, it can be damaged or altered by high temperatures, so heating should be avoided. It is not sensitive to light. ## Storage It is recommended to store specimens in separate, sealed boxes or display cases to protect them from dust and mechanical damage. Due to the small size of the crystals, contact with harder minerals should be avoided.

Sources

IMA Mineral List (CNMNC)