Genkinite

Chemical formula: Pt₄Sb₃

Genkinite is a rare platinum antimonide with a metallic luster, occurring as small grains in ultramafic igneous rocks.

## Characteristics Genkinite is a rare mineral from the antimonide group, chemically a platinum antimonide. It typically occurs as very small, irregular grains or inclusions within other minerals, rarely exceeding 1 mm in size. Due to its composition, it is opaque and has a metallic appearance. ## Physical Properties This mineral is characterized by a hardness ranging from 5.5-6 on the Mohs scale. It has a metallic luster. Its density has not been precisely measured but is high due to its significant platinum content. ## Colors and Varieties Genkinite ranges in color from pale yellow to light brown. No color varieties or commercial varieties are distinguished. ## History and Name Genkinite was first described in 1977 by L.J. Cabri, J.H.G. Laflamme, and J.M. Stewart. The mineral is named in honor of the Soviet mineralogist Adolf Davidovich Genkin (1919-2001), a specialist in platinum-group minerals, for his contributions to the study of the mineralogy of these elements. ## Applications Genkinite has no industrial applications. It is of scientific and collector's interest only as a rare member of the platinum-group minerals.

Properties

Mohs hardness
5.5-6
Luster
Metallic
Density
0
Transparency
Opaque
Crystal system
Tetragonal

Diagnostic features

## Identification Identifying genkinite with the naked eye is practically impossible due to its microscopic size. Identification requires advanced laboratory methods, such as chemical composition analysis (EDS) using a scanning electron microscope (SEM) or X-ray diffraction (XRD) analysis. In studies under a reflected light ore microscope, it exhibits characteristic optical properties. ## Distinguishing from Similar Minerals It can be confused with other small, metallic platinum-group minerals, such as sperrylite, rustenburgite, or platarsite, with which it often co-occurs. Positive identification is only possible based on chemical analysis. ## Crystal Forms Genkinite forms very small, anhedral (irregularly shaped) grains, often as inclusions in other minerals, mainly rustenburgite and platarsite. Traces of its own tetragonal crystal forms are rarely observed.

Geological environment

## Genesis Genkinite is a mineral of magmatic origin. It forms in ultramafic, chromitite-rich layered intrusions, where it crystallizes from residual, platinum- and antimony-rich hydrothermal solutions during the late stages of magma solidification. ## Mineral Associations This mineral co-occurs with other platinum-group minerals (PGM) such as rustenburgite, platarsite, stibiopalladinite, mertieite-II, as well as chromite, chalcopyrite, and pentlandite. ## Localities The most important and classic locality from which genkinite originates is the Onverwacht Mine in the Bushveld Complex, Republic of South Africa. It has also been reported in other areas of this complex (Maandagshoek, Driekop), as well as in the Great Dyke intrusion in Zimbabwe and in nickel and copper deposits in the Norilsk region of Siberia, Russia.

Rarity

Very rare

For collectors

## Quality Criteria As a microscopic mineral, genkinite is not evaluated according to typical criteria such as size or crystal form. The collector's value of a specimen depends on the richness of the mineral association, confirmation of genkinite's presence through analysis, and the renown of the locality. Specimens from the type locality (Onverwacht Mine) with well-documented genkinite in association with other rare platinum-group minerals are most highly prized. ## Popular Localities Specimens from the Onverwacht Mine in South Africa are by far the most valued by specialized collectors, as this is its discovery site.

Care and storage

## Cleaning Genkinite specimens should be cleaned only with extreme care, using compressed air to remove dust. Due to the microscopic size of the grains, mechanical or chemical cleaning is not recommended and can lead to damage or loss of the mineral. ## What to Avoid Avoid contact with chemicals, acids, and cleaning agents. Do not expose it to ultrasonic cleaning. Protect it from scratching by harder minerals. ## Storage Genkinite specimens are best stored in their original, sealed "micromount" boxes to prevent dust accumulation and protect against mechanical damage. Avoid exposure to moisture and contaminants.

External references

Sources

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