Karpenkoite

Chemical formula: Co²⁺₃(V⁵⁺₂O₇)(OH)₂·2H₂O

Karpenkoite is a very rare cobalt vanadate, forming microscopic, purplish-pink crystals with a platy or acicular habit.

## Characteristics Karpenkoite is a hydrated cobalt divanadate. It occurs as very small, platy or acicular crystals, which rarely exceed 0.2 mm in length. These crystals form radial or tangled aggregates, as well as rosette-like clusters. Due to their microscopic size, visual features are difficult to observe without magnification. ## Physical Properties Karpenkoite crystals are flexible and exhibit a vitreous luster. This mineral is transparent to translucent. Its Mohs hardness is approximately 3, and the calculated density is 3.82 g/cm³. ## Colors and Varieties Karpenkoite has a characteristic purplish-pink color with a pale violet streak. No pleochroism has been observed. No varieties of this mineral have been distinguished. ## History and Name The mineral was approved by the IMA in 2015 (IMA2015-059). Its name honors Russian mineralogist and geologist Vladimir Yurievich Karpenko (born 1963), a renowned researcher of minerals from the Kola Peninsula and discoverer of many new mineral species. It was discovered in the dumps of the Little Eva mine in the La Sal district, San Juan County, Utah, USA. ## Uses Karpenkoite has no industrial application. It is solely an object of interest for collectors specializing in rare minerals or micromount minerals.

Properties

Mohs hardness
~3
Color
Orange
Luster
Vitreous
Streak
Pale yellow-orange
Density
3.415
Cleavage
on {001}.
Fracture
Uneven
Transparency
Transparent
Crystal system
Trigonal

Diagnostic features

## Identification Identification of karpenkoite is based on its characteristic purplish-pink color, platy or acicular crystal habit forming radial aggregates, and specific occurrence environment. Final confirmation requires advanced analytical methods, such as Raman spectroscopy or X-ray diffraction (XRD), due to the microscopic size of the crystals. ## Distinguishing from Similar Minerals Karpenkoite can be confused with other secondary, pink or purple cobalt minerals, such as erythrite. However, erythrite usually forms larger, prismatic crystals and has perfect cleavage in one direction, while karpenkoite occurs as fine, flexible needles and plates. ## Crystal Forms Crystals are elongated along the [010] axis and flattened parallel to {001}, adopting the form of plates or needles. They form radial, tangled, or rosette-like aggregates.

Geological environment

## Genesis Karpenkoite is a secondary mineral that forms in the oxidation zones of uranium-vanadium deposits in sandstones. It forms as a result of weathering of primary ore minerals under low-temperature conditions. ## Mineral Associations This mineral co-occurs with other secondary vanadium and cobalt minerals. At the type locality, it was found in association with ansermetite, martyite, cornubite, gypsum, barite, and manganese oxides. ## Localities The only confirmed locality for karpenkoite in the world is its type locality - the Little Eva mine in the La Sal district, San Juan County, Utah, USA.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of karpenkoite specimens is assessed based on the richness and aesthetics of the crystal aggregates on the rock matrix. The most desirable specimens are those with clearly formed, radial or rosette-like clusters of intensely colored crystals. Due to the microscopic nature of the mineral, the quality of the specimen under magnification is crucial. ## Popular Localities The only known source of specimens is the Little Eva mine in Utah, USA. Material from this locality is extremely rare and sought after by collectors specializing in micromount and systematic minerals.

Care and storage

## Cleaning Specimens should be handled with utmost care due to their extreme fragility and small size. Cleaning is not recommended; if absolutely necessary, compressed air can be used from a safe distance. Contact with water, which can damage the mineral, should be avoided. ## What to Avoid Contact with chemicals, acids, and water must be strictly avoided. The crystals are very delicate and sensitive to mechanical shocks. The specimen should not be exposed to high temperatures or ultrasound. ## Storage It is recommended to store specimens exclusively in specialized micromount boxes to protect them from physical damage and dust. Display should be in stable conditions, away from vibrations and sources of moisture.

External references

Sources

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