Pakhomovskyite

Chemical formula: Co<sup>2+</sup><sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>·8H<sub>2</sub>O

Pakhomovskyite is a very rare, hydrated cobalt phosphate, forming characteristic pink, spherical aggregates.

## Characteristics Pakhomovskyite is a hydrated cobalt phosphate, closely related to erythrite. It occurs as small, spherical or hemispherical aggregates with a radial internal structure. The individual crystals forming the aggregates are platy or bladed, but rarely visible to the naked eye. Its most characteristic feature is an intense, pinkish-violet color. ## Physical Properties This mineral is very soft, with a Mohs hardness of 1.5-2. It has a silky or pearly luster on the aggregate surfaces. It is translucent. The density of pakhomovskyite is approximately 2.58 g/cm³. ## Colors and Varieties Pakhomovskyite occurs in a characteristic pinkish-violet color. No color varieties or commercial varieties have been distinguished. ## History and Name The mineral is named in honor of Yakov Dmitrievich Pakhomovsky (1938–2001), a Russian mineralogist and curator of the Fersman Mineralogical Museum collections in Moscow, in recognition of his contribution to the mineralogy of the Kola Peninsula. The mineral was approved by the IMA in 2004, and its discovery was described in 2005. ## Uses Due to its extreme rarity and small size of occurrences, pakhomovskyite has no industrial application. It is solely an object of interest for collectors specializing in rare minerals and for scientists.

Properties

Mohs hardness
1.5-2
Luster
Silky, Pearly
Streak
Light pink
Density
2.58
Cleavage
Perfect on {010}
Fracture
Uneven
Transparency
Translucent
Crystal system
Monoclinic

Diagnostic features

## Identification A key diagnostic feature of pakhomovskyite is its mode of occurrence – small, spherical aggregates with a radial internal structure. The intense pinkish-violet color and silky or pearly luster are also characteristic. Very low hardness is also an important clue. ## Distinguishing from Similar Minerals Pakhomovskyite is visually almost identical to erythrite, with which it forms a solid solution. Distinguishing these two minerals without advanced chemical analysis (determining the dominance of cobalt over nickel) is practically impossible. However, erythrite is much more widespread. ## Crystal Forms This mineral forms spherical or hemispherical aggregates up to 1 mm in diameter. These aggregates are composed of very fine, platy or bladed crystals arranged radially.

Geological environment

## Genesis Pakhomovskyite is a secondary mineral, forming in the oxidation zones of deposits containing cobalt minerals, such as skutterudite. It forms as a result of the weathering of primary ore minerals in the presence of phosphorus. ## Mineral Associations It co-occurs with minerals such as skutterudite, erythrite, annabergite, quartz, calcite, and other rare arsenates and phosphates. ## Localities The only confirmed locality of pakhomovskyite in the world (type locality) is the Bou Azzer deposit in the Drâa-Tafilalet region of Morocco. This is a classic locality for many rare cobalt and nickel minerals.

Rarity

Extremely rare

For collectors

## Quality Criteria For collectors, the intensity and saturation of the pinkish-violet color are most important. Well-formed, spherical aggregates that stand out clearly from the host rock (matrix) are highly valued. Due to their microscopic size, specimens are primarily evaluated under magnification. Contrast with a light matrix, e.g., quartz, enhances the attractiveness of the specimen. ## Popular Localities The only source of pakhomovskyite specimens is the Bou Azzer region in Morocco. Specimens from this locality are the only ones available on the collector's market.

Care and storage

## Cleaning Specimens should be cleaned only very carefully, using a soft brush to remove dust. Due to its low hardness and potential reactivity, contact with water and any chemical agents should be avoided. ## What to Avoid Contact with water, acids, and other chemicals must be absolutely avoided. The mineral is very soft and brittle, susceptible to scratches and mechanical damage. It should be protected from high temperatures, which can lead to dehydration and structural changes. ## Storage It is recommended to store specimens in sealed, closed "micromount" boxes to protect them from dust, moisture, and mechanical damage. Exposure to direct sunlight and changes in humidity should be avoided.

Sources

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