Shijiangshanite

Chemical formula: Pb²⁺₃CaAl(Si₅O₁₄)(OH)₃·3H₂O

Shijiangshanite is an extremely rare, colorless lead, calcium, and aluminum mineral, discovered in China, forming microscopic, bladed crystals.

## Characteristics Shijiangshanite is a hydrated lead, calcium, and aluminum silicate. It occurs as colorless, transparent, bladed or tabular crystals, reaching sizes up to 0.2 x 0.1 x 0.02 mm. These crystals form aggregates or rosettes. It is a secondary mineral, found in the oxidation zone of a lead deposit. ## Physical Properties The mineral is characterized by a hardness of approximately 4 on the Mohs scale. It has a white streak and a vitreous luster. It is transparent. The density calculated based on the chemical formula and unit cell parameters is 4.02 g/cm³. ## History and Name Shijiangshanite was approved as a new mineral by the International Mineralogical Association (IMA) in 2013 (IMA2013-050). Its name comes from its discovery locality – the Shijiangshan mine in Chifeng Prefecture, Inner Mongolia Autonomous Region, China. It was described by Chinese mineralogists Guowu Li, Guangming Li, and others in 2014.

Properties

Mohs hardness
4
Luster
Vitreous
Streak
White
Density
4.02
Cleavage
Perfect on {001}
Fracture
Uneven
Transparency
Transparent
Crystal system
Trigonal

Diagnostic features

## Identification Identification of shijiangshanite is possible only through advanced analytical methods, such as Raman spectroscopy, X-ray diffraction (XRD), and chemical analysis using an electron microprobe (EDS/WDS). Visual identification in the field or even under a microscope is impossible due to its appearance and microscopic size. ## Distinguishing from similar minerals It can be confused with other secondary lead minerals of similar appearance, such as cerussite, anglesite, or other rare silicates. Certain differentiation requires specialized instrumental analysis. ## Crystal forms Crystals are very small, bladed or tabular in habit, elongated along the [010] axis and flattened parallel to {001}. They often form fan-like or rosette aggregates.

Geological environment

## Genesis Shijiangshanite is a secondary mineral that formed in the oxidation zone of a polymetallic lead deposit. It crystallizes in vugs and fissures within the host rock. ## Mineral associations At the type locality, it coexists with quartz, galena, sphalerite, pyrite, chalcopyrite, anglesite, cerussite, hemimorphite, wulfenite, and other unidentified lead silicates. ## Localities The only confirmed occurrence worldwide is its type locality: Shijiangshan lead mine, Linxi County, Chifeng Prefecture, Inner Mongolia Autonomous Region, China.

Rarity

Extremely rare

For collectors

## Quality criteria As a microscopic mineral, the collector's value of shijiangshanite is primarily determined by its extreme rarity and its status as a type specimen. The most highly prized samples are those where crystal aggregates are well-formed, abundant, and clearly visible on the rock matrix, and their identity has been analytically confirmed.

Care and storage

## Cleaning Due to its extreme rarity, microscopic size, and fragility, shijiangshanite specimens should not be cleaned mechanically or chemically. Any attempts at cleaning may destroy the mineral. ## What to avoid Avoid contact with any chemicals, ultrasound, temperature changes, and moisture. The mineral is very delicate and susceptible to mechanical damage. ## Storage Specimens should be stored exclusively in specialized, sealed micromount containers, protecting them from dust, vibrations, and light. Storage under stable room conditions is crucial for preserving the integrity of the sample.

External references

Sources

Read more