Malanite

Chemical formula: Cu₁+(Ir₃+Pt₄+)S₂-₄

Malanite is a rare sulfide of copper, platinum, and iridium, occurring as fine, metallic grains in ultramafic igneous rocks.

## Characteristics Malanite is a very rare mineral from the thiospinel group, composed of copper, platinum, and iridium. It forms small, most often anhedral (irregular) grains not exceeding 0.2 mm in size. It occurs as inclusions within other minerals, primarily in ultramafic rocks. Its appearance is typically metallic, with a steel-gray color. ## Physical Properties This mineral is characterized by a metallic luster and a black streak. It is opaque. Due to the small size of the grains, precise determination of its hardness and density is difficult; the density calculated based on the chemical formula and unit cell parameters is 7.34 g/cm³. ## History and Name The name malanite comes from its discovery locality in the Malan igneous intrusion, located in Hebei Province, China. The mineral was first described in 1995 by Yu Zuxiang and approved by the International Mineralogical Association (IMA). ## Uses Malanite has no industrial applications. Its significance is purely scientific and as a collector's item, as a rare member of the platinum-group minerals.

Properties

Luster: Metallic
Streak: Black
Density: 7.34
Cleavage: None
Fracture: Uneven
Transparency: Opaque
Crystal system: Isometric

Diagnostic features

## Identification Identification of malanite is almost exclusively possible using advanced laboratory techniques, such as chemical composition analysis by electron microprobe (EDS/WDS) and X-ray diffraction (XRD). In polished sections, under a reflected light microscope, it can be observed as fine, steel-gray grains. ## Distinguishing from Similar Minerals It can be confused with other fine, metallic platinum-group sulfides, such as cuproiridsite, cuprorhodsite, or bowieite, with which it often co-occurs. Definitive differentiation requires chemical analysis, which will show the characteristic dominance of copper, iridium, and platinum for malanite. ## Crystal Forms It crystallizes in the isometric system. It usually forms very small, anhedral (irregular) grains or rounded inclusions within other minerals. Poorly developed, octahedral forms are rarely observed.

Geological environment

## Genesis Malanite forms in magmatic processes, crystallizing from residual sulfide melts within ultramafic igneous intrusions, such as chromitites and dunites. It is a mineral of the late stage of magmatic crystallization. ## Mineral Associations It co-occurs with other platinum-group minerals and sulfides. It is most commonly associated with: bornite, chalcopyrite, chromite, cuproiridsite, cuprorhodsite, laurite, osmium, irarsite, and iridium-osmium alloys. ## Localities The most important and confirmed occurrences of this mineral are: - China - Malan intrusion in Hebei Province (type locality). - Russia - Kondyor Massif in Siberia and deposits on the Kola Peninsula. - Sierra Leone - Freetown Layered Complex area. - Brazil - chromitite intrusion in Amapá state.

Rarity

Very rare

For collectors

## Quality Criteria The quality of a malanite specimen is determined not by the appearance of the microscopic grains themselves, but by the richness of the mineral association and the confirmation of its presence through analyses. The most valuable samples are those from the type locality (China) or those in which malanite forms relatively large (for this mineral) aggregates, clearly visible against the host rock or in association with other rare platinum-group minerals. Its value is purely scientific and specialized.

Care and storage

## Cleaning Specimens containing malanite are typically not cleaned due to the microscopic size of the grains and their embedding in the host rock. Any mechanical or chemical intervention could damage or remove the tiny crystals. ## What to Avoid Avoid contact with chemicals, acids, and ultrasonic cleaners. Do not expose it to sudden temperature changes. As a sulfide, it may be sensitive to moisture and oxidation over the long term. ## Storage Store in stable, dry conditions, preferably in a closed display box to protect from dust and contaminants. Protect from direct sunlight.

Sources

IMA Mineral List (CNMNC)