Ankinovichite

Chemical formula: Ni<sup>2+</sup>Al<sub>4</sub>(V<sup>5+</sup>O<sub>3</sub>)<sub>2</sub>(OH)<sub>12</sub>·2H<sub>2</sub>O

Ankinovichite is a very rare nickel and aluminum vanadate, forming microscopic, blue-green aggregates in carbonaceous shales.

## Characteristics Ankinovichite is a hydrated basic nickel and aluminum vanadate. It occurs as very fine, spherical or spherulitic aggregates with a radial internal structure, reaching up to 0.3 mm in size. Individual crystals forming the aggregates are extremely thin, lamellar or fibrous plates. ## Physical Properties Due to the microscopic size of the crystals, most physical properties are difficult to determine precisely. Hardness is estimated at approximately 3 on the Mohs scale. The mineral exhibits a weak, vitreous luster. It is opaque to translucent in very thin fragments. ## Colors and Varieties Ankinovichite is characterized by a vivid, blue-green color. No varieties have been distinguished. ## History and Name The mineral was discovered in deposits of the Balpantach Formation in the Tian Shan Mountains in Kyrgyzstan. It was described and approved as a new mineral species by the International Mineralogical Association (IMA) in 2000. Its name honors the Russian mineralogist and geochemist, Professor Ekaterina Alexandrovna Ankinovich (1911-1991), for her contribution to the study of vanadium deposits in Central Asia. ## Uses Ankinovichite has no industrial application. It is of scientific and collector's interest only as a very rare mineral.

Properties

Mohs hardness
3
Luster
Vitreous
Streak
Pale green
Density
2.63
Cleavage
Perfect on {010}
Fracture
Splintery
Transparency
Translucent
Crystal system
Monoclinic

Diagnostic features

## Identification Field identification of ankinovichite is impossible. Identification requires advanced laboratory techniques, such as scanning electron microscopy (SEM) with EDS analysis, which allows for chemical composition determination, and X-ray diffraction (XRD) to confirm the crystal structure. Its appearance as blue-green spherulitic aggregates on dark shale is characteristic. ## Distinguishing from Similar Minerals It may be confused with other secondary copper, nickel, or vanadium minerals of similar color, such as malachite, chrysocolla, or other rare vanadates. Differentiation relies solely on chemical and structural analysis. ## Crystal Forms It forms spherical, spherulitic aggregates with a radial structure, composed of microscopic, lamellar or fibrous crystals.

Geological environment

## Genesis Ankinovichite is a secondary mineral that forms in the weathering zone. It originates from low-temperature hydrothermal processes or weathering acting on organic matter and sulfide-rich sedimentary rocks, such as black shales. The presence of vanadium, nickel, and aluminum in the parent rock is crucial for its formation. ## Mineral Associations At its type locality in Kyrgyzstan, it co-occurs with quartz, calcite, gypsum, barite, fluorite, as well as rare vanadium minerals like shumianite, steacyite, and minerals from the mica group (phengite). It occurs directly on the surface of black siliceous shales. ## Localities The only confirmed and described locality (type locality) for this mineral is the Balpantach Formation near the Sary-Dzaz River in the Tian Shan Mountains in Kyrgyzstan.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of ankinovichite specimens is assessed based on the size and richness of the aggregates on the rock matrix. The most desirable specimens are those with numerous, well-formed, intensely blue-green spherulites, clearly contrasting with the dark shale background. Due to its microscopic nature, the aesthetics of the "micromount" are key. ## Popular Localities The only source of specimens is its type locality in Kyrgyzstan. Material from this location is extremely limited and rarely appears on the market.

Care and storage

## Cleaning Due to its extreme rarity, fragility, and microscopic size, ankinovichite specimens should not be cleaned mechanically or chemically. It is best to remove dust using compressed air from a safe distance. ## What to Avoid Avoid contact with water, chemicals, ultrasound, and sudden temperature changes. Specimens are very delicate and susceptible to mechanical damage. ## Storage Specimens should be stored exclusively in specialized mineralogical boxes (e.g., "micromount"), protecting them from dust, light, and vibrations. All handling should be done with the utmost care.

Sources

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