Kesebolite-(Ce)

Chemical formula: Ce₃+Ca₂Mn₂+(As₅+O₄)(SiO₃)₃

A very rare cerium, calcium, and manganese silicate-arsenate, forming microscopic, reddish-brown grains.

## Characteristics Kesebolite-(Ce) is a very rare mineral from the silicate and arsenate group, belonging to the rare earth minerals with cerium as the dominant element. It occurs as very small, anhedral grains, usually not exceeding 0.2 mm in size. Specimens are reddish-brown to brownish-red and are typically intergrown with other minerals, forming small aggregates. ## Physical Properties This mineral has a hardness of 5.5 on the Mohs scale. It exhibits a vitreous luster and is translucent. Its density, calculated based on its chemical composition and unit cell parameters, is approximately 4.15 g/cm³. ## Colors and Varieties Kesebolite-(Ce) occurs in uniform reddish-brown and brownish-red colors. There are no distinct color varieties or commercial forms. The suffix -(Ce) in the name is an official suffix indicating the dominance of cerium in the mineral's structure, according to IMA classification. ## History and Name The mineral's name comes from its discovery locality – the Kesebol manganese deposit in the Åmål municipality, Sweden. It was described and recognized as a new mineral in 1997. The suffix -(Ce) indicates that cerium is the dominant rare earth element in its chemical composition. ## Uses Due to its extreme rarity and occurrence only as microscopic grains, kesebolite-(Ce) has no industrial applications. It is solely an object of scientific interest and is valued by specialized collectors of rare minerals and micromounts.

Properties

Mohs hardness: 5.5
Luster: Vitreous
Streak: Pale brown
Density: 4.15
Cleavage: None
Transparency: Translucent
Crystal system: Monoclinic

Diagnostic features

## Identification Identifying kesebolite-(Ce) based on visual characteristics is practically impossible. It occurs as very small, reddish-brown grains. Definitive identification requires advanced analytical techniques, such as X-ray microanalysis (EDS/WDS), to confirm its complex chemical composition with the simultaneous presence of cerium, calcium, manganese, arsenic, and silicon. ## Differentiation from Similar Minerals It can be confused with other small, brown minerals co-occurring in the deposit, such as tephroite or some garnets. Differentiation is possible almost exclusively based on chemical analysis and detailed optical studies under a polarizing microscope. ## Crystal Forms This mineral does not form well-developed crystals. It occurs exclusively as anhedral (irregular), approximately equant grains up to 0.2 mm in size.

Geological environment

## Genesis Kesebolite-(Ce) forms under conditions of regional metamorphism within stratiform, metamorphosed iron and manganese ore deposits. ## Mineral Associations It most commonly co-occurs with minerals such as rhodonite, tephroite, sonolite, barite, calcite, quartz, andradite, and celsian. ## Localities The most important and type locality is the historic Kesebol mine in the Västra Götaland region, Sweden. Its presence has also been confirmed in the Gozaisho mine on Honshu Island, Japan.

Rarity

Very rare

For collectors

## Quality Criteria As a microscopic mineral, the value of a specimen is primarily determined by the confirmation of its identity through analysis. The attractiveness is enhanced by the richness of aggregates (quantity and size of kesebolite grains) on the rock matrix and a clear association with other rare minerals. The specimen must be housed in a "micromount" type box. ## Popular Localities The only source of collectible specimens is the type locality – the Kesebol deposit in Sweden. Specimens from this location are most highly valued by specialized collectors.

Care and storage

## Cleaning Kesebolite-(Ce) specimens are typically micromounts that do not require cleaning. If necessary, dust can only be removed with compressed air or a very soft brush. Avoid contact with water and any chemical agents. ## What to Avoid As an arsenate, this mineral can be potentially toxic, so avoid inhaling dust during any processing. Protect it from contact with acids and do not use ultrasonic cleaners. Stability at high temperatures and under light is unknown, so storage in a dark place is recommended. ## Storage The safest form of storage is a specialized micromount box, which protects the delicate specimen from dust, moisture, and mechanical damage. Each specimen should be precisely labeled.

Sources

IMA Mineral List (CNMNC)