Dmisokolovite

Chemical formula: K₃Cu₂+₅AlO₂(As₅+O₄)₄

Dmisokolovite is an extremely rare potassium, copper, and aluminum arsenate, forming microscopic, green crystals in volcanic fumaroles.

## Characteristics Dmisokolovite is a complex arsenate with a characteristic green or dark green color. It occurs as very small, prismatic or acicular crystals, rarely exceeding 0.2 mm in length. These crystals form radial or chaotically arranged aggregates and coatings on the host rock, reaching up to 0.5 mm in size. Due to its microscopic size, its features are difficult to observe without specialized equipment. ## Physical Properties This mineral is characterized by a vitreous luster and is transparent. Its hardness and density have not yet been precisely determined due to the small size and rarity of the research material. ## Colors and Varieties Dmisokolovite occurs exclusively in shades of green, from light green to very dark. No color or commercial varieties have been distinguished. ## History and Name The mineral's name, approved by the International Mineralogical Association (IMA) in 2012, honors Dmitry Ivanovich Sokolov (1788-1852), a prominent Russian mineralogist and geologist, professor at St. Petersburg University, and author of one of the first Russian mineralogy textbooks. ## Applications Due to its extreme rarity and microscopic size, dmisokolovite has no industrial applications. It is solely an object of scientific interest and a valuable acquisition for specialized micromineral collectors.

Properties

Luster: Vitreous
Streak: Light green
Transparency: Transparent
Crystal system: Monoclinic

Diagnostic features

## Identification Identifying dmisokolovite under amateur conditions is practically impossible. Its green color and acicular form are common to many other copper arsenates. Positive identification requires advanced analytical methods, such as X-ray microanalysis (EDS/WDS) and X-ray diffraction (XRD). A key indicator is its origin from a specific fumarole of the Tolbachik volcano. ## Distinguishing from Similar Minerals Dmisokolovite can be confused with numerous other green arsenates found in the same environment, such as lammerite, bradaczekite, urusovite, or johillerite. The differences between them are subtle and mainly concern chemical composition and crystallographic parameters, making their differentiation impossible without specialized equipment. ## Crystal Forms It forms elongated, prismatic to acicular crystals. Most often, they occur as small, radial aggregates or chaotically arranged clusters on the surface of volcanic rock.

Geological environment

## Genesis Dmisokolovite is a mineral of volcanic origin, formed by sublimation. It crystallizes directly from hot, arsenic-rich gases (exhalations) in high-temperature fumaroles, at a temperature of approximately 450-500°C. ## Mineral Associations It co-occurs with other fumarolic minerals, such as tenorite, hematite, sanidine, sylvine, halite, langbeinite, aphthitalite, as well as other rare arsenates, e.g., alumoklyuchevskite, lammerite, and johillerite. ## Localities The only known locality for dmisokolovite in the world is its type locality – Arsenatnaya fumarole on Tolbachik volcano (Great Tolbachik Fissure Eruption 1975-1976) in Kamchatka, Russia.

Rarity

Extremely rare

For collectors

## Quality Criteria For such a rare micromineral, the main criterion for value is the richness of the specimen – the quantity and density of crystals on the rock matrix. The quality of the crystals themselves is also important: their development, sharpness of forms, and intensity of color. Specimens with well-identified associated minerals, especially other rare arsenates, are also highly valued. ## Popular Localities All specimens available on the collector's market come from a single location in the world – the fumarole of the Tolbachik volcano in Kamchatka. The material primarily originates from collections made during scientific expeditions shortly after the eruption in the 1970s.

Care and storage

## Cleaning Dmisokolovite specimens are extremely delicate and small. Mechanical cleaning is absolutely inadvisable. The only safe method for dust removal is very careful use of a compressed air stream from a safe distance. Avoid contact with water and any chemical agents. ## What to Avoid As a fumarolic mineral, it is likely sensitive to changes in humidity and temperature. Avoid ultrasonic cleaners, all cleaning fluids, acids, and direct, intense light. Touching the crystals can lead to irreversible damage. ## Storage The safest way to store specimens is to place them in a sealed "micromount" box, which protects against dust, moisture, and mechanical damage. It should be kept under stable room conditions.

Sources

IMA Mineral List (CNMNC)