Kitkaite

Chemical formula: NiTeSe

Kitkaite is a very rare nickel selenide-telluride, occurring as microscopic, metallic grains in hydrothermal deposits.

## Characteristics Kitkaite is an extremely rare mineral from the sulfide group, classified as a nickel selenide-telluride. It occurs as very small, anhedral (irregular) grains or hexagonal plates, rarely exceeding fractions of a millimeter in size. For this reason, it is a mineral almost exclusively available to micromineral collectors and scientific institutions. Its identification is only possible using advanced analytical techniques, such as electron microscopy with X-ray microanalysis (SEM-EDS). ## Physical Properties The mineral is opaque and characterized by a strong, metallic luster. Its density is high, at 8.18 g/cm³. Due to the microscopic size of the grains, other physical properties, such as hardness, are difficult to measure precisely by standard methods. ## Colors and Varieties Kitkaite has a color ranging from creamy white to grayish white, sometimes with a delicate, yellowish tint. In reflected light under a microscope, its color is distinctly creamy. No color or commercial varieties are distinguished. ## History and Name The mineral was first described in 1965 by T. A. Häkli, Y. Vuorelainen, and T. G. Sahama. Its name comes from the discovery locality near the Kitka River in the municipality of Kuusamo, Finland, where it was found in ultramafic rock. ## Uses Kitkaite has no industrial applications. It is solely an object of scientific research and interest for specialized collectors of rare minerals.

Properties

Luster
Metallic
Streak
Black
Density
8.18
Cleavage
Perfect on {0001}
Transparency
Opaque
Crystal system
Trigonal

Diagnostic features

## Identification Amateur identification of kitkaite is impossible. Recognition is based on chemical analysis of its composition (ratio of nickel, selenium, and tellurium) under laboratory conditions. A preliminary indication may be its occurrence in association with other rare selenides and tellurides in a specific geological environment. ## Distinguishing from Similar Minerals Kitkaite is visually indistinguishable from many other rare minerals with a metallic luster, such as sederholmite, mäkinenite, clausthalite, or other nickel tellurides and selenides. Definitive differentiation requires quantitative analysis of the elemental composition. ## Crystal Forms Most often, it forms irregular, microscopic grains embedded in other minerals. Less commonly, small, hexagonal lamellae or plates are observed.

Geological environment

## Genesis Kitkaite is a hydrothermal mineral, crystallizing under low-temperature conditions. It forms in calcite-uraninite veins cutting metamorphic rocks or within differentiated mafic and ultramafic intrusions. ## Mineral Associations This mineral co-occurs with other rare selenides and tellurides. Its typical associated minerals include: sederholmite, wilkmanite, mäkinenite, penroseite, clausthalite, as well as uraninite, calcite, karelianite, and pyrite. ## Localities The most important localities for this very rare mineral are: - Kuusamo, Finland (type locality). - Uranium deposits in the Athabasca Basin, Saskatchewan, Canada (including Key Lake and Eagle Point mines). - Příbram district, Czech Republic. - Hope's Nose, Devon, England.

Rarity

Very rare

For collectors

## Quality Criteria The quality of kitkaite specimens is not assessed based on aesthetics, but on scientific and documentary value. The most valuable samples are those in which the presence of the mineral has been confirmed by chemical analysis. An additional advantage is the rich association with other rare selenides and tellurides on a single rock fragment. ## Popular Localities The most known and best-documented specimens, in scientific and collecting circulation, come from hydrothermal uranium veins in the Athabasca Basin, Canada, and from the type locality in Kuusamo, Finland.

Care and storage

## Cleaning Kitkaite specimens are typically microscopic grains embedded in the host rock. They do not require and should not be subjected to mechanical or chemical cleaning. If necessary, dust can be gently removed with compressed air. ## What to Avoid Contact with acids and other chemicals that can destroy the mineral should be strictly avoided. As a selenide-telluride, it is susceptible to oxidation, so it should be protected from moisture and sudden temperature changes. Brittle grains are sensitive to any mechanical damage and abrasion. ## Storage Kitkaite specimens are best stored under stable conditions, in sealed "micromount" containers, which protect them from dust, moisture, and physical damage.

Sources

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