Blatterite

Chemical formula: Sb₅+₃Mn₃+₉Mn₂+₃₅(BO₃)₁₆O₃₂

Blatterite is a very rare, black manganese and antimony borate, forming small, prismatic crystals with a metallic luster.

## Characteristics Blatterite is a complex manganese, antimony, and iron borate belonging to the orthopinakiolite group. It occurs as black, opaque, prismatic crystals, often elongated and longitudinally striated. It typically forms small, millimeter-sized crystals, which can occur individually but more often form radial or parallel aggregates. Its appearance is characteristic of many rare manganese oxides and borates from similar environments. ## Physical Properties This mineral is characterized by a Mohs hardness of 6, making it relatively scratch-resistant. It has a metallic to submetallic luster, which is clearly visible on fresh crystal surfaces. Its density is approximately 4.8 g/cm³, making it noticeably heavy for its size. It is opaque and has a brownish-black streak. ## Colors and Varieties Blatterite is monochromatic – it occurs exclusively in black. No color varieties or commercial forms are known. ## History and Name The mineral was first described in 1986 by Pete J. Dunn and colleagues. Its name honors Fritz Blatter (1897-1985), a Swiss mineral collector who specialized in collecting specimens from classic localities such as Långban in Sweden and Franklin in the USA, known for the occurrence of rare manganese minerals. ## Uses Due to its extreme rarity, blatterite has no industrial applications. It is solely an object of scientific interest and a prized acquisition for specialized collectors of rare minerals.

Properties

Mohs hardness: 6
Luster: Metallic to Sub-Metallic
Streak: Brownish-black
Density: 4.8
Cleavage: Perfect on {010}
Fracture: Uneven
Transparency: Opaque
Crystal system: Orthorhombic

Diagnostic features

## Identification Features facilitating the identification of blatterite include its black color, metallic luster, relatively high hardness (6 on the Mohs scale), and high density. The prismatic habit of the crystals and their tendency to form radial aggregates are also characteristic. A key clue is its association with other rare manganese minerals in a specific geological environment. ## Distinguishing from Similar Minerals Blatterite can be easily confused with other black, metallic manganese minerals occurring in the same localities, such as pinakiolite, orthopinakiolite, jacobsite, or hausmannite. Pinakiolite is particularly similar. Certain distinction of these minerals under amateur conditions is practically impossible and usually requires advanced analytical methods, such as X-ray microanalysis (EDS/WDS), which can confirm the presence of antimony, crucial for the definition of blatterite. ## Crystal Forms It crystallizes in the orthorhombic system. It forms elongated, prismatic crystals, often with distinct striations on the side faces, parallel to the elongation axis. Crystals rarely occur individually, more often forming fan-shaped, radial, or nearly parallel aggregates in rock fissures.

Geological environment

## Genesis Blatterite is a mineral of metamorphic origin. It forms in manganese and iron ore deposits that have undergone contact or regional metamorphism at relatively high temperatures. It is a product of reactions between manganese minerals and boron- and antimony-rich fluids. ## Mineral Associations Depending on the locality, blatterite co-occurs with other, often rare minerals. In the type locality (Sweden), it is accompanied by hausmannite, jacobsite, tephroite, sonolite, and manganberzeliite. In Namibia, its main associated minerals are hausmannite and barite. ## Localities This is a mineral with a very limited number of confirmed occurrences. The two main and most important localities for collectors worldwide are: - Brattfors Mine within the Nordmark Odal Field, Filipstad, Värmland, Sweden - this is the type locality. - Kombat Mine, Grootfontein, Otjozondjupa, Namibia.

Rarity

Very rare

For collectors

## Quality Criteria The collector's value of blatterite is primarily determined by the quality and size of the crystals. Most desirable are specimens with sharp, well-formed, lustrous crystals, ideally forming aesthetic, radial aggregates. Since most crystals are very small (on the order of a few millimeters), any specimen with larger crystals is highly prized. The matrix and the presence of other rare associated minerals, which enhance the attractiveness and scientific value of the specimen, are also of great importance. ## Popular Localities The most valued specimens come from two main localities: the Brattfors mine in Sweden (type locality) and the Kombat mine in Namibia. Specimens from both locations are sought after by specialized collectors of rare minerals and systematic collectors.

Care and storage

## Cleaning Blatterite specimens should be cleaned with great care. A soft brush is best for removing dust. In case of heavier soiling, distilled water and a very soft brush can be used, but after cleaning, the specimen should be immediately and thoroughly dried. Ultrasonic cleaners are strongly discouraged, as they can damage fragile crystals. ## What to Avoid This mineral is sensitive to strong acids. Contact with household and laboratory chemicals should be avoided. Despite its relatively high hardness, the crystals are brittle and susceptible to mechanical damage, so they should be protected from impacts and drops. ## Storage Collector's specimens of blatterite are best stored in separate, sealed membrane boxes or in display cases with soft lining to protect them from dust and mechanical damage. A label with the name and locality is crucial due to its rarity and resemblance to other minerals.

Sources

IMA Mineral List (CNMNC)