Grigorievite

Chemical formula: Cu₂+₃Fe₃+₂Al₂(V₅+O₄)₆

Grigorievite is a very rare vanadate of copper, iron, and aluminum, forming black microcrystals in volcanic fumaroles.

## Characteristics Grigorievite is a complex vanadate with a black color and vitreous luster. It occurs as very small, tabular or flattened crystals, not exceeding 0.2 mm in size. These crystals form aggregates in the form of crusts and coatings on volcanic rocks. Due to the microscopic size of the crystals, its features are difficult to observe without specialized equipment. ## Physical Properties This mineral is opaque. Its density, calculated based on chemical composition and crystal structure, is 3.86 g/cm³, but there are no measured data. Hardness has not been determined. ## Colors and Varieties Grigorievite is monochromatic – it occurs exclusively in black. No colored varieties are known. ## History and Name The mineral was named in honor of Dmitry Pavlovich Grigoriev (1909–2003), a prominent Russian mineralogist and crystallographer, founder of the school of mineralogical genetics. It was identified as a new mineral in materials from high-temperature fumaroles of Bezymianny volcano on the Kamchatka Peninsula, Russia. ## Uses Grigorievite has no commercial or industrial applications. As an extremely rare mineral with microscopic crystals, it is solely an object of scientific research and interest for specialized micromineral collectors.

Properties

Luster: Vitreous
Streak: Brown
Density: 3.86
Transparency: Opaque
Crystal system: Triclinic

Diagnostic features

## Identification Identification of grigorievite is impossible without advanced laboratory techniques, such as X-ray diffraction (XRD) and chemical microanalysis (EDS/WDS). Key diagnostic features include its unique chemical composition (presence of copper, iron, aluminum, and vanadium), black color, vitreous luster, and occurrence in the specific environment of high-temperature volcanic fumaroles. ## Distinguishing from Similar Minerals It can be confused with other black, opaque minerals found in fumaroles, such as tenorite, hematite, or bannermanite. Definitive differentiation from these minerals requires chemical analysis. ## Crystal Forms It forms flattened, tabular crystals, which most often occur as dense aggregates, clusters, and crusts on the surface of the host rock.

Geological environment

## Genesis Grigorievite is a mineral of volcanic origin, formed by sublimation from gases in high-temperature fumaroles (at temperatures from 600 to 820°C). It crystallizes directly from the gas phase on the surfaces of volcanic rocks near exhalation vents. ## Mineral Associations This mineral co-occurs with other rare fumarolic minerals. The most common associations include bannermanite, shcherbinaite, hewettite, alarsite, euchlorine, fedotovite, tenorite, and hematite. ## Localities The only confirmed locality of grigorievite in the world is its type locality – Bezymianny volcano on the Kamchatka Peninsula, Russia.

Rarity

Extremely rare

For collectors

## Quality Criteria For such a rare micromineral, collectible value is not assessed in terms of aesthetics in the traditional sense. The most important criterion is the richness of the specimen – the denser and more extensive the crust of crystals, the more valuable the specimen. Additional value is provided by the presence of well-formed (though still microscopic) crystals and co-occurrence with other rare associated minerals. ## Popular Localities Specimens come exclusively from one place in the world – Bezymianny volcano in Kamchatka. For this reason, there are no "popular" localities in the commercial sense; this location is accessible almost exclusively to scientific expeditions.

Care and storage

## Cleaning Grigorievite specimens are extremely delicate and usually consist of microscopic crystals on a rock matrix. Mechanical or chemical cleaning is not recommended. Any dust can only be removed with a very gentle stream of compressed air. ## What to Avoid Contact with water, acids, detergents, and all chemicals should be strictly avoided. Specimens must not be subjected to ultrasonic cleaning, rapid changes in temperature, or humidity, as a fumarolic mineral it may be unstable under variable conditions. ## Storage It is recommended to store specimens in stable, dry conditions, preferably in sealed "micromount" boxes, which protect against dust, mechanical damage, and changes in humidity.

Sources

IMA Mineral List (CNMNC)