Namansilite

Chemical formula: NaMn³⁺Si₂O₆

Namansilite is a rare, dark red sodium manganese silicate from the clinopyroxene group, discovered in Russia at the end of the 20th century.

## Characteristics Namansilite is a sodium manganese silicate belonging to the clinopyroxene group. It forms granular or fibrous aggregates, and well-formed crystals are rare. Its color ranges from dark, brownish-red to purplish-red, which is a characteristic visual feature of this mineral. ## Physical Properties This mineral is characterized by a hardness of 6-7 on the Mohs scale, making it relatively resistant to scratching. It has a density of approximately 3.51 g/cm³ and a vitreous luster. Crystals, though rare, can be transparent. ## Colors and Varieties The dominant colors of namansilite are shades of red: dark brownish-red and purplish-red. No distinct color or commercial varieties have been identified. ## History and Name The name "namansilite" is an acronym derived from the mineral's chemical composition: Sodium (Latin: *Natrium* - **Na**), **Man**ganese, and Silicon (Latin: *Silicium* - **Sil**). It was formally described and recognized as a new mineral in 1989, following its discovery in the Ir-Nimi manganese deposit in the Khabarovsk Krai, Russia. ## Applications Namansilite has no industrial significance. Its occurrence is so rare that it is solely an object of interest for collectors specializing in rare minerals or pyroxene systematics.

Properties

Mohs hardness
6-7
Luster
Vitreous
Streak
Brownish violet
Density
3.51
Cleavage
{110}
Fracture
Uneven
Transparency
Transparent
Crystal system
Monoclinic

Diagnostic features

## Identification Helpful features for identifying namansilite include its characteristic brownish-red or purplish-red color, relatively high hardness (6-7), and brownish-purple streak. It occurs in a specific geological environment, which is also an important clue. ## Distinguishing from Similar Minerals Namansilite can be confused with other manganese pyroxenes or pyroxenoids, such as rhodonite. However, rhodonite is usually pink, has a lower hardness (5.5-6.5), and perfect cleavage in two directions. Accurate identification often requires advanced analytical methods, such as X-ray diffraction (XRD). ## Crystal Forms Namansilite most commonly forms granular, fibrous, or radial aggregates. Well-formed, prismatic crystals typical of monoclinic pyroxenes are rarely observed.

Geological environment

## Genesis Namansilite is a mineral formed as a result of metamorphic processes acting on manganese-rich sedimentary deposits. It forms under conditions of high pressure and relatively low temperature, in rocks such as quartzite. ## Mineral Associations This mineral co-occurs with other manganese minerals. In its type locality, it was found in association with quartz, piemontite, alurgite (a manganese-rich variety of muscovite), braunite, and hematite. ## Localities The most important and well-documented occurrences of namansilite are in Russia, in the Khabarovsk Krai, within the Ir-Nimi manganese deposit (Dzhavodi and Zaoblachnyi areas), which is its type locality. Beyond Russia, its occurrence has also been reported in the Cerchiara mine in Italy and in Ehime Prefecture, Japan.

Rarity

Very rare

For collectors

## Quality Criteria The most prized specimens by collectors are those with well-formed, even if small, transparent crystals of intense, purplish-red color. Contrastive placement on a light rock matrix, for example on quartz, also enhances its attractiveness. Due to its rarity, even rich granular or fibrous aggregates are sought after. ## Popular Localities By far the most desirable specimens come from the type locality in Russia (Ir-Nimi deposit), where the best-formed crystals originate. Specimens from other, few localities are also valuable from a collector's perspective due to their rarity.

Care and storage

## Cleaning Namansilite specimens should be cleaned very carefully, using a soft brush to remove dust. If necessary, distilled water can be used, and then the specimen should be thoroughly dried. Ultrasonic cleaners should be avoided, as they can damage aggregates. ## What to Avoid The mineral should be protected from contact with strong acids and other aggressive chemicals. Due to its chemical composition, prolonged exposure to moisture is not recommended. Sudden temperature changes should also be avoided. ## Storage Collectible namansilite specimens are best stored in stable conditions, in closed display boxes or cabinets, away from direct sunlight and dust. It is advisable to isolate it from harder minerals to prevent scratching.

External references

Sources

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