Niksergievite
Chemical formula: Ba₂Al₃(Si,Al)₄O₁₀(CO₃)(OH)₆·nH₂O
Niksergievite is a very rare mineral from the mica group, a hydrated barium aluminosilicate, forming tiny, hexagonal flakes with a pearly luster.
Properties
- Mohs hardness
- 1-1.5
- Color
- White with greenish tint
- Luster
- Pearly
- Streak
- white
- Density
- 3.16
- Cleavage
- (001)
- Fracture
- Micaceous
- Transparency
- Translucent
- Crystal system
- Monoclinic
Diagnostic features
## Identification Niksergievite is difficult to identify visually without specialized equipment. It is recognized by its occurrence as very small, creamy-white, hexagonal flakes with a pearly luster. It forms characteristic rosette-like and spherulitic aggregates. Key factors are its occurrence location (calcite-dolomite veins in the Kovdor massif) and its association with other rare minerals. ## Distinguishing from Similar Minerals It can be mistaken for other microcrystalline micas or light-colored clay minerals. It is distinguished from talc and similar minerals by its higher pearly luster and specific aggregate form. Certain identification requires advanced analytical methods, such as X-ray diffraction (XRD) or chemical analysis (EDS). ## Crystal Forms Crystals are in the form of small, thin, hexagonal or pseudohexagonal flakes. They typically form aggregates in the shape of rosettes, spherulites, or irregular scaly clusters.
Geological environment
## Genesis Niksergievite forms under hydrothermal conditions. It was found in calcite-dolomite veins cutting fenite rocks, which in turn are associated with the carbonatite Kovdor massif on the Kola Peninsula in Russia. ## Mineral Associations This mineral is associated with calcite, dolomite, quartz, clinochlore, fluorite, pyrite, as well as rarer minerals such as manasseite, quintinite, and kovdorskite. ## Localities The only confirmed locality of niksergievite in the world is its type locality – the phlogopite quarry in the Kovdor massif, on the Kola Peninsula, Murmansk Oblast, Russia.
Rarity
Extremely rare
For collectors
## Quality Criteria The quality of niksergievite specimens is assessed based on the richness and visibility of aggregates on the host rock. Specimens with well-formed, distinct rosettes or spherulites that contrast with the matrix are most valued. Due to the microscopic nature of the mineral, the size of individual crystals is not a key criterion; rather, the abundance and aesthetics of the entire aggregate are important. ## Popular Localities All known specimens come from a single location in the world – the Kovdor massif in Russia. It is an extremely difficult mineral to acquire, available almost exclusively at specialized shows or through exchange with research institutions and collectors possessing material from the type locality.
Care and storage
## Cleaning Niksergievite specimens are extremely delicate and usually occur as tiny coatings or aggregates on the host rock. Mechanical or chemical cleaning is not recommended. Any attempts at cleaning may destroy the fragile flakes of the mineral. If dust removal is necessary, it can be done very carefully using a soft brush or a photographic blower with minimal force. ## What to Avoid Contact with water, acids, detergents, and other chemicals must be strictly avoided. The mineral is very soft (Mohs hardness 1), so it must be protected from any physical contact, scratching, or vibrations. It should not be heated or exposed to temperature changes. ## Storage Specimens should be stored exclusively in stable, sealed "micromount" boxes to protect them from dust, mechanical damage, and moisture. Store in a dry place at a constant temperature.