Putoranite

Chemical formula: Cu₁.₁Fe₁.₂S₂

Putoranite is a rare copper iron sulfide, forming small, hexagonal crystals with a metallic luster.

## Characteristics Putoranite is a copper iron sulfide, closely related to talnakhite and mooihoekite. It typically occurs as small, anhedral grains, rarely exceeding 0.5 mm, often forming aggregates with other sulfides. It is characterized by a metallic luster and a brass-yellow color, which on fresh surfaces may have a pinkish or brownish tint. ## Physical Properties This mineral is opaque and has a hardness of approximately 4 on the Mohs scale. Its density is quite high, around 4.6 g/cm³. It exhibits distinct cleavage in one direction. The luster is strongly metallic. ## Colors and Varieties Its color is described as brass-yellow, often with a pinkish or brownish tint on a fresh fracture. No varieties of this mineral have been distinguished. ## History and Name The name putoranite comes from its discovery location – the Putoran (Putorana) Plateau in north-central Siberia, Russia. The mineral was described and approved by the IMA in 1980. ## Applications Due to its rarity and occurrence as microscopic grains, putoranite has no industrial applications. It is solely an object of scientific and collector interest within micromineral collections.

Properties

Mohs hardness
4.5
Color
Yellow
Luster
Metallic
Streak
Black
Density
0
Cleavage
Good on {0001}
Fracture
Uneven
Transparency
Opaque
Crystal system
Isometric

Diagnostic features

## Identification Identification of putoranite is extremely difficult without advanced analytical methods. Preliminary identification is based on its brass-yellow color with a pinkish tint, metallic luster, and co-occurrence with other copper and iron sulfides in nickel-copper deposits. Definitive identification requires chemical analysis (EDS) and X-ray diffraction (XRD) methods. ## Distinguishing from Similar Minerals It can be confused with many other sulfides of similar color, such as chalcopyrite, pyrite, talnakhite, or mooihoekite. Distinguishing it from these minerals with the naked eye is practically impossible. Chalcopyrite is usually more yellow, and pyrite is brighter. Talnakhite and mooihoekite have very similar properties and require specialized studies for differentiation. ## Crystal Forms It forms small, anhedral (irregularly shaped) grains and rare, tabular or hexagonal crystals, usually smaller than 0.5 mm.

Geological environment

## Genesis Putoranite forms as a result of hydrothermal processes within differentiated gabbro-dolerite intrusions, associated with copper and nickel sulfide deposits. It crystallizes at relatively low temperatures, below 200°C, often as a product of alteration of other high-temperature sulfides. ## Mineral Associations It co-occurs with other sulfides, such as talnakhite, mooihoekite, chalcopyrite, cubanite, pentlandite, as well as with magnetite and platinum group minerals. ## Localities The most important and classic localities for this mineral are in Russia, within the Norilsk and Talnakh intrusions in Siberia (Putoran Plateau). It has also been reported in the Bushveld Complex in South Africa and in Sudbury, Canada, which are among the world's most important nickel and copper ore mining regions.

Rarity

Very rare

For collectors

## Quality Criteria As a micromineral, putoranite is valued primarily for its confirmed analytical identity. Specimens showing rare, well-formed crystals, even if microscopic in size, are most highly prized. The richness of associations with other rare sulfides on a single rock fragment is also important. ## Popular Localities Undoubtedly, the most valued and classic specimens come from the Norilsk and Talnakh regions in Siberia, Russia. These are the type localities for this mineral.

Care and storage

## Cleaning Putoranite specimens, usually as inclusions in the host rock, should be cleaned very carefully. The safest method is to use compressed air to remove dust. Avoid washing with water and any chemicals that may react with sulfides. ## What to Avoid Avoid contact with water, acids, and other chemicals that can lead to oxidation and destruction of the mineral. High humidity is also harmful and can cause tarnish to form on its surface. Protect it from high temperatures. ## Storage Putoranite specimens are best stored in dry conditions, in closed, airtight containers (so-called "micromount boxes") away from sources of moisture. Display should occur under stable environmental conditions to prevent its degradation.

External references

Sources

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