Manganokaskasite

Chemical formula: (Mo,Nb⁵⁺)S₂·(Mn²⁺₁-xAlx)(OH)₂+x

Manganokaskasite is a rare, black sulfide mineral with perfect cleavage, discovered in the Khibiny Massif on the Kola Peninsula in Russia.

## Characteristics Manganokaskasite is a sulfide mineral from the kaskasite group, closely related to molybdenite. It occurs as very small, hexagonal, platy crystals, usually not exceeding 0.2 mm in size. It forms aggregates and clusters. Its characteristic features are its iron-black color and metallic luster. ## Physical Properties This mineral is very soft, with a hardness of 1 on the Mohs scale, meaning it can be scratched with a fingernail. It has perfect, micaceous cleavage in one plane, which causes it to easily split into thin flakes. Its density is approximately 4.09 g/cm³. It is opaque. ## Colors and Varieties So far, it has only been observed in an iron-black color. No color varieties or commercial varieties have been distinguished. ## History and Name The name "manganokaskasite" refers to its chemical composition – the dominance of manganese in its structure – and its relation to the mineral kaskasite. It was described as a new mineral in 2013 by a team of mineralogists (V.V. Karpenko et al.) based on material collected in the Khibiny Massif in Russia. ## Applications Due to its extreme rarity and microscopic crystal sizes, manganokaskasite has no industrial applications. It is of purely scientific significance and is an object of interest for specialized collectors of rare minerals.

Properties

Mohs hardness
1
Luster
Metallic
Density
4.09
Cleavage
{001} perfect and mica-like
Fracture
Micaceous
Transparency
Opaque
Crystal system
Trigonal

Diagnostic features

## Identification Identification of manganokaskasite under amateur conditions is practically impossible. It requires advanced analytical methods such as Raman spectroscopy or chemical analysis using an electron microprobe (EDS/WDS). Visual features such as black color, metallic luster, and platy habit are common to many other minerals. ## Distinguishing from Similar Minerals It can be confused with graphite, molybdenite, or hematite in the specularite form. It differs from graphite and molybdenite in its chemical composition (presence of manganese and niobium). Distinguishing it from other black, platy minerals without specialized equipment is unfeasible. ## Crystal Forms It forms very small, hexagonal, tabular or platy crystals. It occurs as single flakes or small clusters embedded in the host rock.

Geological environment

## Genesis Manganokaskasite forms under hydrothermal conditions within highly differentiated alkaline massifs. In its type locality (Mount Kaskasnyunchorr), it was found in nepheline-sodalite pegmatites, where it crystallizes in voids and fractures. ## Mineral Associations This mineral co-occurs with other rare minerals typical of the Khibiny Massif, such as sodalite, nepheline, microcline, aegirine, eudialyte, lorenzenite, lamprophyllite, cancrinite, as well as galena and sphalerite. ## Localities The only confirmed occurrence of manganokaskasite in the world is its type locality: Mount Kaskasnyunchorr in the Khibiny Massif, on the Kola Peninsula, Murmansk Oblast, Russia.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of a manganokaskasite specimen is primarily assessed based on the richness and size of the crystals on the rock matrix. Since the crystals are microscopic, any specimen with visible, well-formed flakes is considered valuable. Contrast with surrounding minerals (matrix) is also important. ## Popular Localities The only source of specimens is the type locality in the Khibiny Massif, Russia. Collector material is extremely difficult to obtain and appears on the market very rarely, mainly circulating among specialists and advanced systematic mineral collectors.

Care and storage

## Cleaning Specimens of manganokaskasite are extremely delicate. Any mechanical cleaning should be avoided. If absolutely necessary, compressed air (from a safe distance) can be used to remove dust. Do not use water or any chemicals. ## What to Avoid The mineral is very soft (hardness 1), so touching, rubbing, and contact with harder objects should be avoided. It should be protected from moisture, acids, and other chemical agents. Due to its nature, ultrasonics and sudden temperature changes should be avoided. ## Storage Specimens should be stored exclusively in sealed, padded "micromount" boxes to protect them from mechanical damage, dust, and moisture. Display is not recommended due to the fragility and small size of the crystals.

External references

Sources

Read more