Mangani-pargasite

Chemical formula: NaCa₂(Mg₄Mn³⁺)(Si₆Al₂)O₂₂(OH)₂

Mangani-pargasite is a rare mineral from the amphibole group, distinguished by its dark red color and occurrence in metamorphic manganese rocks.

## Characteristics Mangani-pargasite is a complex silicate of sodium, calcium, magnesium, and manganese, belonging to the amphibole supergroup. It forms elongated, prismatic crystals, often with a fibrous habit or in the form of granular aggregates. Its most characteristic feature is its intense, dark red to reddish-brown color, resulting from the presence of trivalent manganese (Mn³⁺) in its crystal structure. ## Physical Properties This mineral is characterized by a hardness of 5-6 on the Mohs scale. It has a vitreous luster and is usually translucent. Its density is approximately 3.16 g/cm³. It exhibits perfect cleavage in two directions, typical for amphiboles. ## Colors and Varieties The dominant and only known color of mangani-pargasite is dark red, transitioning to reddish-brown. No color varieties or commercial varieties are distinguished. ## History and Name The name "mangani-pargasite" refers to its chemical composition – the dominance of manganese (mangani) at a specific site in the crystal structure – and its relationship to pargasite, another mineral from the amphibole group. It was formally described and recognized as a new mineral species relatively recently, which is typical for many rare members of complex mineral groups. ## Uses Mangani-pargasite has no industrial applications. Its significance is limited to the scientific sphere, as an indicator of specific metamorphic conditions, and to advanced collecting due to its rarity and attractive color.

Properties

Mohs hardness
5-6
Color
red to reddish brown
Luster
Vitreous
Streak
Light red
Density
3.127
Cleavage
{110}
Fracture
Uneven
Transparency
Transparent
Crystal system
Monoclinic

Diagnostic features

## Identification The key diagnostic feature of mangani-pargasite is its unique dark red color, combined with a prismatic crystal habit and occurrence in a specific geological environment (manganese-rich metamorphic rocks). The characteristic amphibole cleavage at an angle of approximately 120° may be visible in larger crystals. ## Distinguishing from Similar Minerals This mineral can be confused with other red silicates, such as eudialyte or piemontite. Differentiation often requires advanced research methods, such as chemical analysis (EDS) or X-ray diffraction (XRD). In field conditions, the main clue is its association with other manganese minerals. ## Crystal Forms Mangani-pargasite most often forms elongated, columnar, or prismatic crystals. It also occurs as fibrous aggregates, radial aggregates, or disordered granular aggregates within the rock mass.

Geological environment

## Genesis It is a mineral typical of metamorphic rocks that have undergone metamorphism under amphibolite facies conditions. Its formation is associated with regional metamorphism of manganese- and sodium-rich sediments. It crystallizes at relatively high temperatures and pressures. ## Mineral Associations Mangani-pargasite often coexists with other minerals characteristic of manganese rocks, such as quartz, rhodochrosite, spessartine (manganese garnet), tephroite, sonolite, as well as other manganese amphiboles and pyroxenes. ## Localities The most important and well-known locality, which is also the type locality (place of discovery), is the Kombat Mine in the Otjozondjupa region of Namibia. This is the main locality from which specimens available on the collector's market originate. Other confirmed occurrences include the Långban deposit in Sweden.

Rarity

Very rare

For collectors

## Quality Criteria The most highly valued mangani-pargasite specimens are those with well-formed, sharply terminated crystals of intense, deep red color and high luster. Crystals contrasting with a light rock matrix, e.g., with white quartz, are particularly desirable. Crystal size is also a key factor – specimens with crystals exceeding one centimeter in length are rare and highly prized. ## Popular Localities The vast majority of the best quality collector specimens come from the Kombat Mine in Namibia. This is the classic and most sought-after locality for this mineral.

Care and storage

## Cleaning Specimens should only be cleaned mechanically, using a soft, dry brush or paintbrush to remove dust. If necessary, compressed air can be used. Due to its rarity and potential sensitivity, contact with water and chemical agents should be avoided. ## What to Avoid All chemicals should be avoided, especially acids, which can damage the mineral's surface. Do not heat or expose to sudden temperature changes. Prolonged exposure to strong sunlight may not be advisable, although there is a lack of detailed research on this topic. ## Storage Collector specimens of mangani-pargasite, especially those with well-formed crystals, should be stored in separate, padded boxes or display cases to prevent abrasions and mechanical damage. They should be protected from dust and moisture.

External references

Sources

Read more