Reznitskyite

Chemical formula: CaMg(V<sup>5+</sup>O<sub>4</sub>)F

Reznitskyite is an extremely rare calcium and magnesium vanadate, forming microscopic, hexagonal crystals of an intensely orange color.

## Characteristics Reznitskyite is a mineral from the vanadate group, distinguished by its unique chemical composition containing calcium, magnesium, vanadium, and fluorine. It occurs as extremely small, hexagonal, tabular crystals, rarely exceeding 0.2 mm in size. These crystals form rosette-like or spherulitic aggregates. Due to its microscopic size, it is a mineral primarily accessible to specialized collectors and scientific institutions. ## Physical Properties Reznitskyite crystals are characterized by a vitreous luster. They are transparent to translucent. Hardness and density have not been precisely measured due to the small size of the samples; however, the density calculated based on the formula and unit cell parameters is approximately 3.19 g/cm³. ## Colors and Varieties This mineral is characterized by a vivid, orange color. No varieties are known. ## History and Name Reznitskyite was discovered in the fumaroles of the Tolbachik volcano in Kamchatka, Russia. It was approved as a new mineral species by the International Mineralogical Association (IMA) in 2022 (IMA2022-094). Its name honors Leonid Zinovyevich Reznitsky (born 1939), a Russian geologist and mineralogist, specialist in the mineralogy of the southern Baikal region.

Properties

Luster
Vitreous
Streak
Light orange
Density
3.19
Cleavage
Perfect on {0001}
Transparency
Transparent to translucent
Crystal system
Hexagonal

Diagnostic features

## Identification Identification of reznitskyite is possible only through advanced analytical methods, such as Raman spectroscopy and chemical analysis using an electron microprobe (EDS/WDS). Visually, at the occurrence site, it can be suspected based on its orange color and the form of small, spherulitic aggregates. ## Distinguishing from Similar Minerals Many other rare vanadates with similar colors occur in the fumaroles of the Tolbachik volcano. Certain differentiation from them without specialized equipment is impossible. ## Crystal Forms Reznitskyite forms hexagonal, tabular crystals that combine into spherulitic and rosette-like aggregates up to 0.3 mm in size.

Geological environment

## Genesis Reznitskyite is a product of volcanic fumarolic activity. It forms as a result of the sublimation of volcanic gases in exhalative zones, crystallizing on the surface of basaltic rocks at temperatures above 450°C. ## Mineral Associations This mineral co-occurs with other rare fumarolic minerals, such as hematite, tenorite, orthoclase (arsenian variety), fluorophlogopite, anhydrite, sylvite, halite, as well as other vanadates, e.g., markhinite and grigoryevite. ## Localities The only confirmed locality of reznitskyite in the world is its type locality - Arsenievskaya fumarole on the second cinder cone of the Northern Breakthrough of the Great Fissure Eruption of Tolbachik volcano in Kamchatka, Russia.

Rarity

Extremely rare

For collectors

## Quality Criteria As a microscopic mineral, the quality of a specimen is primarily determined by the abundance and size of crystal aggregates on the rock matrix. The most desirable samples are those with clearly formed, undamaged spherulites of intense orange color, well-distinguished from the substrate. ## Popular Localities The only source of specimens is the type locality on Tolbachik volcano in Kamchatka. Material from this location is extremely difficult to obtain.

Care and storage

## Cleaning Due to the extreme rarity and microscopic size of the crystals, reznitskyite specimens should not be mechanically or chemically cleaned. Any contaminants should be left intact to avoid damaging the delicate aggregates. ## What to Avoid Contact with any chemicals, ultrasound, and sudden temperature changes should be avoided. Specimens should be protected from dust and vibrations. ## Storage Storage under stable conditions, in a specialized, sealed "micromount" box, is absolutely essential. Exposure to sunlight should be avoided, although there is no specific data on its effect on the mineral.

Sources

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