Zhonghongite

Chemical formula: Cu₁+₂₈Cu₂+(As₃+,Sb₃+)₁₂S₂-₃₃

Zhonghongite is an extremely rare, metallic copper, arsenic, and antimony sulfide, forming tiny, cubic crystals.

## Characteristics Zhonghongite is a very rare mineral from the sulfide group, first described in 2024. It occurs as extremely small, metallic grains and incomplete crystals up to 100 micrometers in size. When observed under a microscope in reflected light, it has a grayish-white color with a slight yellowish tint. ## Physical Properties This mineral is characterized by a metallic luster and is opaque. Its Mohs hardness is 3.5, classifying it as a relatively soft mineral. The density calculated based on its chemical formula and unit cell parameters is 5.11 g/cm³. ## History and Name The name "zhonghongite" honors Professor Zhonghong Wang (born 1964), a Chinese crystallographer from Peking University, for his contributions to mineralogy and crystallography. The mineral was discovered in material from the Bairendaba copper deposit in China and officially approved by the International Mineralogical Association (IMA) in 2023 (IMA2023-080).

Properties

Mohs hardness: 3.5
Luster: Metallic
Streak: Black
Density: 5.11
Cleavage: None
Fracture: Uneven
Transparency: Opaque
Crystal system: Cubic

Diagnostic features

## Identification Identification of zhonghongite is only possible using advanced laboratory methods, such as chemical composition analysis (EDS/WDS) with an electron microprobe and X-ray diffraction (XRD) to confirm its crystal structure. Visual identification, even under a microscope, is insufficient. ## Distinguishing from Similar Minerals Under a microscope, it can be confused with other metallic sulfides and sulfosalts, such as tennantite, tetrahedrite, or chalcopyrite. Definitive differentiation requires chemical analysis, which will reveal the unique proportion of copper, arsenic, and antimony. ## Crystal Forms Zhonghongite forms very small, incompletely developed crystals with a cubic habit, reaching up to 100 μm in size. It occurs as individual grains or aggregates intergrown with other minerals.

Geological environment

## Genesis This mineral forms as a result of hydrothermal processes. At its type locality (Bairendaba), it was found in polymetallic veins cutting through volcanic rocks (andesites and dacites). ## Mineral Associations Zhonghongite co-occurs with other ore minerals such as chalcopyrite, tennantite, bornite, galena, sphalerite, pyrite, and digenite. ## Localities The only confirmed occurrence of zhonghongite in the world is its type locality – the Bairendaba copper deposit, located in Chifeng Prefecture, Inner Mongolia Autonomous Region, China.

Rarity

Extremely rare

For collectors

## Quality Criteria Zhonghongite is a mineral of purely scientific significance and does not appear on the collector's market in the form of macroscopic specimens. Its value lies in the very fact of its existence and analytical confirmation within the host rock. Any verified specimen, regardless of "quality," is extremely valuable to research institutions.

Care and storage

## Cleaning Due to its extreme rarity and microscopic crystal size, zhonghongite specimens are not subject to standard cleaning. Any attempts at mechanical or chemical cleaning may irreversibly destroy the mineral. Specimens should only be analyzed under laboratory conditions. ## What to Avoid Avoid contact with chemicals, moisture, sudden temperature changes, and any form of mechanical stress (abrasion, impact). As a sulfide, it may be susceptible to oxidation in a humid environment. ## Storage Specimens containing zhonghongite, embedded in host rock or polished sections, must be stored under stable conditions, preferably in a dry, sealed container (desiccator) or a specialized micromineral box, away from dust and contaminants.

Sources

IMA Mineral List (CNMNC)