Gutkovaite-Mn

Chemical formula: CaK<sub>2</sub>Mn<sup>2+</sup>(Ti<sup>4+</sup>,Nb<sup>5+</sup>)<sub>4</sub>(Si<sub>4</sub>O<sub>12</sub>)<sub>2</sub>(O,OH)<sub>4</sub>·5H<sub>2</sub>O

Gutkovaite-Mn is a very rare mineral from the labuntsovite group, forming small, prismatic, brown crystals.

## Characteristics Gutkovaite-Mn is a complex silicate of titanium, niobium, manganese, calcium, and potassium, belonging to the labuntsovite group. It occurs as very small, prismatic or acicular crystals, reaching up to 0.3 mm in length. It forms radial aggregates or appears as single, overgrown crystals. It is a transparent mineral with a vitreous luster. ## Physical Properties Gutkovaite-Mn crystals exhibit a hardness of approximately 5 on the Mohs scale. They are brittle and have an uneven fracture. The mineral's density has been calculated at 2.96 g/cm³. ## Colors and Varieties This mineral is characterized by a color ranging from light brown to reddish-brown. The streak is light brown. No varieties have been distinguished. ## History and Name Gutkovaite-Mn was discovered in material originating from the Khibiny Massif on the Kola Peninsula in Russia. It was described and approved as a new mineral species by the International Mineralogical Association (IMA) in 2002 (IMA2002-044). The name honors the Russian crystallographer Nina Nikolaevna Gutkova (1896–1942), a researcher of minerals from the Khibiny and Lovozero massifs. The suffix "-Mn" in the name indicates the dominance of manganese at a specific position in the crystal structure, distinguishing it from other potential members of the series.

Properties

Mohs hardness
5
Luster
Vitreous
Streak
Light brown
Density
2.96
Cleavage
Good on {100}
Fracture
Uneven
Transparency
Transparent
Crystal system
Monoclinic

Diagnostic features

## Identification Identification of gutkovaite-Mn is only possible using advanced analytical methods, such as X-ray diffraction (XRD) and chemical microanalysis (EDS/WDS). Visually, it is indistinguishable from many other microscopic, brown minerals. ## Distinguishing from Similar Minerals It can be confused with other minerals from the labuntsovite group (e.g., kuzmenkoite-Mn, organovaite-Mn) and other fine-grained titanium silicates occurring in the same environment. Definitive distinction requires specialized laboratory tests. ## Crystal Forms It forms elongated, prismatic or acicular crystals, often gathered in radial or chaotic aggregates. The crystals are very small, usually not exceeding 0.3 mm in length.

Geological environment

## Genesis Gutkovaite-Mn forms under hydrothermal conditions in the late stages of crystallization of nepheline-syenite pegmatites, crystallizing in voids and fissures. ## Mineral Associations It co-occurs with minerals such as aegirine, natrolite, microcline, lorenzenite, lomonosovite, eudialyte, as well as other minerals from the labuntsovite group. ## Localities The only confirmed occurrence of this mineral (type locality) is Mount Kukisvumchorr in the Khibiny Massif on the Kola Peninsula in Russia.

Rarity

Very rare

For collectors

## Quality Criteria As a microscopic mineral, gutkovaite-Mn is primarily valued by collectors specializing in rare minerals and micromounts. Specimens with well-formed, rich crystal aggregates, clearly visible under a microscope and set on a contrasting matrix, are most highly prized. Association with other rare minerals is also important. ## Popular Localities All collector material originates from a single location in the world – the Khibiny Massif in Russia. Specimens from this locality are the only ones available on the market.

Care and storage

## Cleaning Due to its extreme rarity and small crystal size, mechanical cleaning is not recommended. If necessary, compressed air can be used to remove dust. Avoid contact with water and chemicals. ## What to Avoid Avoid ultrasonic cleaners, steam cleaners, acids, and all solvents. The mineral is brittle, so protect it from impacts and scratching. Store away from moisture. ## Storage Gutkovaite-Mn specimens, due to their microscopic nature, should be stored in specialized micromount boxes, protecting them from dust, humidity, and mechanical damage.

Sources

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