Vanadio-pargasite

Chemical formula: NaCa₂(Mg₄V³⁺)[Si₆Al₂]O₂₂(OH)₂

Vanadio-pargasite is a rare, bright green amphibole group mineral, distinguished by its vanadium content, found in marbles.

## Characteristics Vanadio-pargasite is a mineral belonging to the amphibole group, specifically to the pargasites. Its characteristic feature is the presence of vanadium in its chemical composition, which distinguishes it from other minerals in this group. It forms elongated, prismatic crystals, often occurring as granular aggregates or embedded in the host rock. Its appearance is typical of many amphiboles, but it is distinguished by its intense, bright green color. ## Physical Properties This mineral has a hardness of 6 on the Mohs scale, placing it on par with orthoclase. It has a vitreous luster and is translucent. Its density is approximately 3.05 g/cm³, which is a typical value for silicates of similar composition. ## Colors and Varieties Vanadio-pargasite occurs in shades from bright green to emerald green. The intensity and hue of the color depend directly on the concentration of vanadium ions (V³⁺) in its crystal structure. No named commercial or color varieties are distinguished. ## History and Name The mineral's name derives from its chemical composition – it indicates the dominance of vanadium at a specific position 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, and its discovery is associated with studies of metamorphic marbles from the Baikal region. ## Uses Due to its rarity, vanadio-pargasite has no industrial applications. It is solely an object of interest for collectors of rare minerals and scientists studying metamorphic processes and the crystal chemistry of amphiboles.

Properties

Mohs hardness
6
Luster
Vitreous
Streak
White
Density
3.05
Cleavage
(110)
Fracture
Uneven
Transparency
Translucent
Crystal system
Monoclinic

Diagnostic features

## Identification The key diagnostic feature of vanadio-pargasite is its intense, bright green or emerald color, combined with its occurrence in a specific geological environment – skarns and marbles. The prismatic habit of the crystals and the cleavage characteristic of amphiboles are also important clues. ## Distinguishing from Similar Minerals Vanadio-pargasite can be confused with other green minerals found in metamorphic rocks, such as diopside, uvarovite, vesuvianite, or other amphiboles (e.g., actinolite). It differs from diopside often by a more intense color and a different cleavage angle. Uvarovite (garnet) is much harder and crystallizes in the isometric system. Final distinction from other vanadium or chromium amphiboles requires advanced chemical analyses (EDS/WDS). ## Crystal Forms This mineral forms columnar, elongated crystals with a hexagonal cross-section, which is typical for amphiboles. It also occurs as granular, fibrous aggregates or as inclusions in calcitic marbles.

Geological environment

## Genesis Vanadio-pargasite is a mineral of metamorphic origin. It forms under conditions of high temperature and pressure, within carbonate rocks (limestones and dolomites) metamorphosed in the amphibolite facies. Its crystallization is associated with the presence of vanadium in the primary sediment or in metasomatic solutions. ## Mineral Associations This mineral co-occurs with other minerals typical of marbles and skarns. It is most often accompanied by calcite, dolomite, diopside, tremolite, phlogopite, scapolite, titanite, as well as other vanadium minerals, such as goldmanite (garnet) or karelianite. ## Localities The most important and typical occurrence (type locality) of vanadio-pargasite is the Pereval marble quarry in Sludyanka, Irkutsk Oblast, Russia, near Lake Baikal. This is the only confirmed and well-documented locality of this mineral in the world.

Rarity

Very rare

For collectors

## Quality Criteria The most valued by collectors are specimens with well-formed, sharp, and undamaged crystals of intense, emerald-green color. Aesthetic compositions, where green vanadio-pargasite crystals contrast with a white, calcitic matrix, are also highly prized. The size of the crystals and their transparency also significantly increase the value of the specimen. ## Popular Localities The only source of collector's specimens is the Pereval quarry in the Sludyanka region of Russia. Specimens from this locality are unique and highly sought after by specialized collectors of rare minerals and systematic minerals.

Care and storage

## Cleaning Vanadio-pargasite specimens should be cleaned very carefully. It is best to use a soft brush to remove dust. If necessary, the specimen can be rinsed in distilled water, then thoroughly dried with a gentle stream of air or left to air dry at room temperature. ## What to Avoid Avoid contact of the mineral with acids and strong chemicals, which can damage its surface. It should not be heated or exposed to sudden temperature changes. Despite a hardness of 6, it is brittle and sensitive to impact. ## Storage Collector's specimens of vanadio-pargasite, especially those with well-formed crystals, should be stored in separate, padded boxes to prevent abrasion and mechanical damage. Protect from dust and moisture. It can be displayed in enclosed showcases.

External references

Sources

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