Cheremnykhite
Chemical formula: Pb<sup>2+</sup><sub>3</sub>Zn<sup>2+</sup><sub>3</sub>Te<sup>6+</sup>O<sub>6</sub>(V<sup>5+</sup>O<sub>4</sub>)<sub>2</sub>
Cheremnykhite is an extremely rare lead-zinc tellurate-vanadate, forming microscopic, yellow crystals in volcanic fumaroles.
Description
## Characteristics Cheremnykhite is a complex tellurate-vanadate belonging to the dugganite group. It occurs as very small, hexagonal crystals with a prismatic or tabular habit, not exceeding 0.2 mm in size. It also forms granular aggregates. The mineral is characterized by an intense yellow to orange-yellow color and a strong, adamantine luster, which makes it visually attractive despite its microscopic size. ## Physical Properties The mineral's luster is adamantine, and its transparency is described as translucent. The density calculated based on the chemical formula and unit cell parameters is 6.76 g/cm³. Hardness has not yet been determined due to the small size of the crystals. ## Colors and Varieties This mineral is known exclusively in shades from yellow to orange-yellow. No color or commercial varieties have been distinguished. ## History and Name Cheremnykhite was first described in 2000 by L.P. Vergasova and co-workers. Its name honors Pavel Vasilyevich Cheremnykh (1914-1994), a Russian geologist from Kamchatka, who dedicated many years to studying the Tolbachik volcano - the discovery site of the mineral. ## Applications Due to its extreme rarity and microscopic size, cheremnykhite has no industrial application. It is solely an object of scientific interest and a valuable acquisition for specialized micromount mineral collectors.
Diagnostic features
## Identification Identifying cheremnykhite based on visual characteristics is practically impossible and requires advanced analytical methods, such as energy-dispersive spectroscopy (EDS) or wavelength-dispersive spectroscopy (WDS) to confirm its unique chemical composition (presence of Pb, Zn, Te, and V). In a collection, it is identified based on a label with confirmed analysis and its characteristic occurrence locality. ## Distinguishing from Similar Minerals Visually, it can be confused with other yellow minerals found in the fumarole environment of Tolbachik volcano. Chemical analysis is crucial for differentiation, as it will reveal the specific combination of elements. Minerals with a similar appearance from this locality, such as some arsenates, will have a completely different composition. ## Crystal Forms It forms hexagonal, prismatic, or thick, tabular crystals, usually up to 0.2 mm in size. It also occurs as fine-grained aggregates and clusters on the surface of basaltic scoria.
Geological environment
## Genesis Cheremnykhite is a fumarolic mineral. It forms as a result of high-temperature (500-600°C) exhalative activity of a volcano. It crystallizes directly from volcanic gases, depositing as coatings and small crystals on porous basaltic scoria near fumarole vents. ## Mineral Associations This mineral co-occurs with a rich assemblage of other fumarolic minerals. The most common associations include tenorite, hematite, averievite, alarsite, arfvedsonite, bradaczekite, coparsite, euchlorine, fedotovite, johillerite, lammertite, langbeinite, nabokoite, and urusovite. ## Localities The only confirmed occurrence of cheremnykhite in the world is its type locality - Arsenatnaya fumarole on the second cinder cone of the Northern Breakthrough of the Great Fissure Eruption of Tolbachik volcano in Kamchatka, Russia.
Rarity
Extremely rare
Collector aspects
## Quality Criteria For "micromount" type minerals, such as cheremnykhite, the value of a specimen is determined by several factors. The most important is the presence of well-formed, sharp crystals with a distinct hexagonal outline. Specimens rich in crystals, forming aesthetic groups on a small matrix surface, are highly prized. An attractive visual association with other rare minerals from this locality is an additional advantage. ## Popular Localities All known cheremnykhite specimens come from a single, classic locality - Tolbachik volcano in Kamchatka. This is the only source of this mineral, and specimens from this locality are highly valued by specialized collectors.
Care and storage
## Cleaning Cheremnykhite specimens are extremely small and fragile. Mechanical cleaning (brushes) and chemical cleaning are absolutely not recommended. The only permissible methods are very gentle dust removal using a photographic blower or a stream of compressed air from a distance. ## What to Avoid Avoid contact with all chemicals, acids, and detergents. The mineral, as a fumarole product, may be sensitive to changes in humidity and temperature. Ultrasonic cleaners must not be used. It should be protected from direct sunlight, which can cause fading. ## Storage Specimens should be stored in stable, dry conditions. The best solution is a specialized "micromount" box, which protects the delicate specimen from mechanical damage, dust, and sudden environmental changes.