Zheshengite

Chemical formula: Pb₂+₄Zn₂+Zn₂+₂(As₅+O₄)₂(PO₄)₂(OH)₂

Zheshengite is a rare lead-zinc arsenate-phosphate, forming tiny, tabular crystals with a vitreous luster.

## Characteristics Zheshengite is a mineral from the arsenate and phosphate group, chemically classified as a basic lead-zinc arsenate-phosphate. It occurs as very small, tabular or platy crystals, rarely exceeding 0.2 mm in length. The crystals are transparent to translucent, with a vitreous luster. Due to their small size, its visual characteristics are difficult to assess without magnification. ## Physical Properties This mineral is characterized by a hardness of approximately 4 on the Mohs scale. Its density is high, which is typical for lead-bearing minerals, and is about 5.86 g/cm³. The luster is described as vitreous. ## Colors and Varieties Zheshengite is colorless or has a pale yellow hue. No varieties have been distinguished. ## History and Name The mineral's name honors Zhesheng Gu (born 1943), a Chinese mineral collector who provided the first sample of this mineral for study. It was officially recognized by the International Mineralogical Association (IMA) in 2021 (IMA2021-039). The discovery was made on material from the Jinding lead-zinc mine in the Nujiang Lisu Autonomous Prefecture, Yunnan Province, China. ## Uses Zheshengite has no industrial application. Its significance is purely scientific and for collectors, as a very rare and recently discovered mineral species.

Properties

Mohs hardness: 4
Luster: Vitreous
Streak: White
Density: 5.86
Cleavage: Perfect on {100}
Fracture: Uneven
Transparency: Transparent to Translucent
Crystal system: Monoclinic

Diagnostic features

## Identification Identification of zheshengite is possible only through advanced analytical methods, such as Raman spectroscopy, X-ray diffraction (XRD), and chemical analysis (EDS/WDS). Visual identification in the field or in a collection is impossible due to the microscopic size of the crystals and their resemblance to many other secondary minerals. ## Distinguishing from Similar Minerals It can be confused with other secondary lead and zinc minerals, such as anglesite, cerussite, hemimorphite, or other rare arsenates. Differentiation requires specialized laboratory equipment. ## Crystal Forms Zheshengite forms very small, thin, tabular crystals with a hexagonal outline, often grouped into small aggregates or rosettes. The crystals are elongated along one of the axes.

Geological environment

## Genesis Zheshengite is a secondary mineral that forms in the oxidation (weathering) zones of lead and zinc ore deposits. It forms as a result of reactions of phosphate and arsenate-rich solutions with primary ore minerals, such as galena and sphalerite. ## Mineral Associations At the type locality (Jinding mine), it co-occurs with minerals such as hydrocerussite, sphalerite, galena, pyrite, and anglesite. It is found in vugs and fractures within the zinc-lead ore. ## Localities The only confirmed locality for zheshengite worldwide is the Jinding lead-zinc mine, in Lanping County, Nujiang Lisu Autonomous Prefecture, Yunnan Province, China.

Rarity

Extremely rare

For collectors

## Quality Criteria As a "micromount" type mineral, the value of a specimen is primarily determined by the quality and size of the crystals, even though they are microscopic. The most desirable are well-formed, sharp, transparent crystals forming aesthetic groups on a contrasting rock matrix. The presence of associated minerals is also important. ## Popular Localities The only source of specimens is its type locality – the Jinding mine in China. Specimens from this location are highly sought after by collectors specializing in rare and systematic minerals.

Care and storage

## Cleaning Due to the extreme rarity and small size of the crystals, mechanical cleaning is not recommended. If absolutely necessary, compressed air can be used to remove loose dust particles. Avoid contact with water and chemicals. ## What to Avoid Avoid all acids and strong bases, which can react with the mineral's components. As a lead and arsenic-bearing mineral, it is potentially toxic – avoid inhaling dust and wash hands after any contact. ## Storage Zheshengite specimens should be stored in stable conditions, in sealed "micromount" containers, to protect them from mechanical damage and dust. Keep them away from moisture and direct sunlight.

Sources

IMA Mineral List (CNMNC)