Cuprozheshengite
Chemical formula: Pb²⁺₄Cu²⁺Zn²⁺₂(As⁵⁺O₄)₂(PO₄)₂(OH)₂
Cuprozheshengit is a rare mineral from the arsenate and phosphate group, distinguished by its green, tabular crystals and complex chemical composition.
Properties
- Mohs hardness
- 2.5-3
- Color
- apple green to greenish blue
- Luster
- Vitreous
- Streak
- white
- Density
- 5.91
- Cleavage
- {011}
- Fracture
- Irregular/Uneven
- Transparency
- Transparent
- Crystal system
- Triclinic
Diagnostic features
## Identification Identification of cuprozheshengit is almost exclusively possible using advanced analytical methods, such as Raman spectroscopy or electron microprobe chemical analysis (EDS/WDS). Visually, at the occurrence site, it can be suspected based on its pale green color and the form of small, tabular crystals in paragenesis with other rare secondary minerals. ## Distinguishing from Similar Minerals It can be confused with other secondary copper minerals, such as zheshengit, tsumebite, or duftite. Zheshengit has an almost identical appearance and requires chemical analysis for differentiation (higher zinc content). Tsumebite crystallizes in a different system (triclinic) and forms distinct crystal habits. Duftite has a similar color but usually forms spherical aggregates or crusts. ## Crystal Forms Cuprozheshengit forms thin, tabular crystals with a hexagonal outline, often elongated, forming radial aggregates or irregular clusters.
Geological environment
## Genesis It is a secondary mineral, formed in the oxidation zones (gossans) of polymetallic deposits rich in lead, zinc, copper, and arsenic. It forms as a result of the alteration of primary sulfide ores under low temperature and pressure conditions, with the involvement of phosphate-rich waters. ## Mineral Associations At the type locality (Kintore Opencut, Broken Hill, Australia), it co-occurs with minerals such as zheshengit, anglesite, goethite, hematite, hinsdalite-corkite, libethenite, mimetite, pyromorphite, plumbogummite, pseudomalachite, quartz, and tsumebite. ## Localities The only confirmed locality for cuprozheshengit worldwide is its type locality: Kintore Opencut in Broken Hill, Yancowinna County, New South Wales, Australia.
Rarity
Extremely rare
For collectors
## Quality Criteria As a "micromount" type mineral, the quality of a specimen is primarily determined by the sharpness and development of the crystals, their size (though always small), and the richness of the cluster on the rock matrix. Specimens with well-defined, undamaged crystals forming aesthetically pleasing, radial aggregates are desirable. A contrasting matrix, such as dark goethite, enhances visual appeal. ## Popular Localities The only source of specimens is the Kintore Opencut mine in Broken Hill, Australia. Material from this location is extremely rare and sought after by specialized collectors of systematic and "micromount" minerals.
Care and storage
## Cleaning Due to its extreme rarity, small crystal size, and brittleness, mechanical cleaning is highly inadvisable. If absolutely necessary, compressed air can be used from a safe distance to remove loose dust particles. Contact with water and any chemicals should be avoided. ## What to Avoid Ultrasonics, steam cleaners, acids, solvents, and sudden temperature changes must be strictly avoided. The mineral is brittle and chemically sensitive. It should be protected from direct sunlight, which can cause fading. ## Storage Cuprozheshengit specimens should be stored exclusively in specialized, sealed "micromount" boxes, away from vibrations, dust, and moisture. It is best to store them under stable room conditions, in a dark place.