Leybovite-K

Chemical formula: KCu₂+Na(MgFe₃+)(As₅+O₄)₃

Leybovite-K is an extremely rare arsenate of the alluaudite group, discovered in fumarolic products of Tolbachik volcano in Kamchatka.

## Characteristics Leybovite-K is a mineral of the alluaudite group, occurring as very fine, tabular crystals not exceeding 10x30x50 micrometers in size. It forms aggregates and coatings on the surface of basaltic scoria. The crystals are transparent and have a vitreous luster. ## Physical Properties Due to the microscopic size of the crystals, many physical properties, such as hardness, density, or fracture, have not been precisely determined. Density was calculated based on the formula and unit cell parameters and is 4.23 g/cm³. ## Colors and Varieties This mineral is characterized by a green color. No varieties are known. ## History and Name Leybovite-K was approved as a new mineral species by IMA in 2023 (IMA2023-035). Its name honors Russian mineralogist and collector Mikhail B. Leybov (born 1950) for his contribution to the study of Kamchatka minerals. The suffix "-K" refers to the dominance of potassium in its chemical composition. It was discovered in the products of fumarolic activity on Tolbachik volcano in Kamchatka, Russia. ## Uses Leybovite-K has no industrial applications. It is of purely scientific significance and is of interest to specialized micromineral collectors.

Properties

Luster: Vitreous
Streak: Green
Density: 4.23
Transparency: Transparent
Crystal system: Monoclinic

Diagnostic features

## Identification Identification of Leybovite-K is possible only with advanced analytical methods, such as Raman spectroscopy or electron microprobe chemical analysis (EDS/WDS). Visual identification in the field or in a collection is impossible due to its microscopic size and similarity to other secondary copper and arsenic minerals. ## Distinguishing from Similar Minerals It can be confused with other green arsenates occurring in the same environment, such as erychalcum, johillerite, or other minerals of the alluaudite group. Definitive differentiation requires specialized research equipment. ## Crystal Forms Crystals are very small, tabular, and form porous aggregates or thin coatings.

Geological environment

## Genesis Leybovite-K forms as a sublimation product in the environment of active volcanic fumaroles, crystallizing directly from volcanic gases at temperatures of about 450-500°C. It is a secondary mineral, forming on basaltic scoria. ## Mineral Associations This mineral coexists with other arsenates and sulfates formed under similar conditions, such as johillerite, erychalcum, hematite, tenorite, arcanite, langbeinite, aphthitalite, sylvite, and halite. ## Localities The only known locality in the world (type locality) is the Yadovitaya fumarole on the Second Northern Cone of the Great Fissure Eruption of Tolbachik volcano in Kamchatka, Russia.

Rarity

Extremely rare

For collectors

## Quality Criteria Due to its extreme rarity and microscopic size, every analytically confirmed specimen is scientifically valuable. For micromineral collectors, the most desirable specimens are those with the largest (though still microscopic) and well-formed crystals, forming rich aggregates on a small piece of host rock.

Care and storage

## Cleaning Specimens of this mineral are extremely delicate and small. Mechanical or chemical cleaning is not recommended. If necessary, compressed air (from a safe distance) can be used to remove dust. ## What to Avoid Avoid contact with water, chemicals, ultrasound, and any vibrations or impacts. Sudden temperature changes can be harmful. ## Storage Specimens should be stored exclusively in specialized micromount boxes, protecting them from dust, moisture, and mechanical damage. Display is only possible under a microscope.

Sources

IMA Mineral List (CNMNC)