Paraershovite

Chemical formula: Na<sub>3</sub>K<sub>3</sub>Fe<sup>3+</sup><sub>2</sub>Si<sub>8</sub>O<sub>20</sub>(OH)<sub>4</sub>·4H<sub>2</sub>O

Paraershovite is a very rare, brown sodium, potassium, and iron silicate, forming unique platy crystals.

## Characteristics Paraershovite is a complex layered silicate from the ershovite group, characterized by a unique chemical composition including sodium, potassium, and iron. It forms aggregates of platy or lamellar crystals, which can reach up to 1 cm in length. Its structure and appearance are typical for minerals found in ultrabasic pegmatites. ## Physical Properties This mineral is relatively soft, with a hardness of approximately 3 on the Mohs scale. It has a vitreous luster. It is transparent to translucent. The density is approximately 2.69 g/cm³. ## Colors and Varieties Paraershovite occurs in shades of brown, from light brown to reddish-brown. No varieties have been distinguished. ## History and Name The mineral's name refers to its structural and chemical similarity to ershovite. The prefix "para-" indicates polymorphism – these minerals have the same chemical composition but differ in crystal structure. It was first described in 2000 by a team of mineralogists (N.V. Chukanov et al.) based on material from the Khibiny Massif in Russia. ## Uses Paraershovite has no industrial application. Its significance is purely scientific and as a collector's item due to its extreme rarity and unique crystal chemistry.

Properties

Mohs hardness
3
Luster
Vitreous
Streak
Light brown
Density
2.69
Cleavage
Perfect on {001}
Fracture
Uneven
Transparency
Transparent to Translucent
Crystal system
Triclinic

Diagnostic features

## Identification Key diagnostic features include its brown color, platy crystal habit, vitreous luster, and occurrence in a specific geological environment – agpaitic pegmatites. Its instability upon contact with water is also characteristic. ## Distinguishing from Similar Minerals It can be confused with ershovite, from which it is virtually impossible to distinguish visually; this requires advanced X-ray diffraction (XRD) analysis. From other brown silicates (e.g., some micas), it is distinguished by its crystal habit and mineral paragenesis. ## Crystal Forms Paraershovite forms elongated, lamellar or platy crystals, often gathered in radial or chaotic aggregates. Crystals are elongated along the [100] axis and flattened parallel to {001}.

Geological environment

## Genesis It is a hydrothermal mineral, crystallizing in the late stages of pegmatite formation within alkaline and agpaitic massifs. It forms in vugs and fractures within these rocks. ## Mineral Associations It most commonly co-occurs with other rare alkaline minerals, such as ershovite, natrosilite, rasvumite, villiaumite, aegirine, lomonosovite, umbite, and kostylevite. It is also accompanied by more common minerals like microcline and nepheline. ## Localities The only confirmed locality for paraershovite in the world is its type locality: Mount Koashva in the Khibiny Massif on the Kola Peninsula, Russia.

Rarity

Extremely rare

For collectors

## Quality Criteria The most prized specimens are those with well-formed, sharp, and undamaged crystals of intense, brown color. Contrast with the rock matrix and the presence of rare associated minerals are important. Due to the size of the crystals, even centimeter-sized specimens are considered exceptional. ## Popular Localities The only source of specimens is the Khibiny Massif in Russia. Material from this location is extremely difficult to acquire and appears on the collector's market sporadically.

Care and storage

## Cleaning Specimens should only be cleaned very carefully, using a soft brush to remove dust. Due to its reactivity with water, all contact with liquids should be avoided. Wet cleaning is prohibited. ## What to Avoid Contact with water, acids, and other chemicals must be strictly avoided. The mineral is unstable in water and easily undergoes alteration. It should be protected from high temperatures and humidity, which can lead to its degradation. ## Storage It is recommended to store in a sealed, dry container, preferably with a desiccant (e.g., silica gel). It should be displayed away from direct sunlight and heat sources, in stable humidity conditions.

Sources

Read more