Parwelite

Chemical formula: Mn₂+₁₀Sb₅+₂As₅+₂Si₂O₂₄

Parwelite is a very rare manganese, antimony, and arsenic silicate, forming small, brownish-red crystals, known from only one locality in the world.

## Characteristics Parwelite is an extremely rare mineral from the silicate group, with a complex chemical composition including manganese, antimony, and arsenic. It occurs as very small, tabular or prismatic crystals, rarely exceeding 1 mm in size. It typically forms small aggregates or single, scattered crystals on the surface of the host rock. Its appearance is inconspicuous, and identification requires specialized research methods. ## Physical Properties Parwelite crystals exhibit a hardness of approximately 5 on the Mohs scale. They have a luster described as vitreous to resinous. They are transparent to translucent. The mineral's density is relatively high, around 4.53 g/cm³. ## Colors and Varieties Parwelite occurs in uniform colors, from brownish-red to dark red. No color varieties or commercial forms are known. ## History and Name The mineral was discovered in the historic Långban mine in Filipstad Municipality, Värmland region, Sweden. It was described and approved as a new mineral species in 1972. Its name honors Alexander Parwel (1896-1979), a chemist working at the Swedish Museum of Natural History, who performed the first chemical analyses of this mineral.

Properties

Mohs hardness: 5
Luster: Vitreous to resinous
Streak: Light brown
Density: 4.53
Cleavage: Imperfect/poor on {001}
Fracture: Uneven
Transparency: Transparent to translucent
Crystal system: Monoclinic

Diagnostic features

## Identification Amateur identification of parwelite is practically impossible. It requires advanced analytical techniques, such as X-ray diffraction (XRD) and chemical microanalysis (EDS/WDS). Visual characteristics, such as brownish-red color, small crystal size, and occurrence in association with Långban minerals, can only provide an initial indication. ## Distinguishing from Similar Minerals It can be confused with many other rare Långban minerals of similar color, such as some garnets, pyrochroite, katoptrite, or magnussonite. Definitive distinction is possible only based on chemical composition and crystal structure analysis. ## Crystal Forms It forms very small, tabular crystals with a prismatic habit, often flattened. Crystals are usually poorly formed and occur as single individuals or small, irregular aggregates.

Geological environment

## Genesis Parwelite forms as a result of metamorphic processes in iron and manganese ore deposits. Its occurrence is associated with skarns and metamorphosed carbonate rocks. It formed under unique geochemical conditions, characterized by high concentrations of manganese, arsenic, and antimony, typical of the Långban deposit. ## Mineral Associations This mineral co-occurs with other rare minerals characteristic of its type locality. It is most commonly found in association with katoptrite, magnussonite, tephroite, berzeliite, manganostibite, and various garnet varieties. ## Localities The only confirmed locality for parwelite in the world is the Långban mine in Värmland, Sweden. This is the type locality for this mineral.

Rarity

Extremely rare

For collectors

## Quality Criteria As a "micromount" type mineral, its value is primarily determined by the quality and size of the crystals, even though they are microscopic. Specimens with well-formed, sharp crystals of intense, brownish-red color are most prized. The aesthetics of the rock matrix and the presence of rare associated minerals are also important. ## Popular Localities All known parwelite specimens originate from a single location – the historic Långban mine in Sweden. This is one of the most famous mineralogical localities in the world, known for the occurrence of hundreds of unique mineral species.

Care and storage

## Cleaning Due to its extreme rarity and small crystal size, mechanical cleaning is highly inadvisable. If absolutely necessary, compressed air (from a safe distance) can be used to remove loose dust particles. Avoid contact with water and any chemicals. ## What to Avoid Ultrasonic cleaners, steam cleaners, acids, solvents, and all chemical agents should be strictly avoided. The mineral is sensitive to shocks and impacts, which can destroy delicate crystals. It should be protected from sudden temperature changes. ## Storage Parwelite specimens should be stored exclusively in specialized, sealed "micromount" boxes that protect them from dust, moisture, and mechanical damage. Display should occur under stable conditions, away from direct sunlight and sources of vibration.

Sources

IMA Mineral List (CNMNC)