Pingguite

Chemical formula: Bi<sup>3+</sup><sub>6</sub>Te<sup>6+</sup><sub>2</sub>O<sub>15</sub>

Pingguite is a very rare bismuth tellurite, forming microscopic, tabular crystals of an intense yellow color.

## Characteristics Pingguite is an extremely rare mineral from the tellurite group, chemically a complex bismuth and tellurium oxide. It occurs as very small, thin, tabular crystals, rarely exceeding 0.2 mm. These crystals often form rosette-like or spherulitic aggregates. Due to its microscopic size, it is a mineral of interest mainly to specialized collectors of rare species. ## Physical Properties Pingguite crystals exhibit a vitreous to adamantine luster. They are transparent to translucent. Hardness and density have not been precisely measured due to the small size and rarity of the material, but the density calculated based on the formula and cell parameters is 8.45 g/cm³. ## Colors and Varieties This mineral is characterized by an intense, canary-yellow color. No varieties are known. ## History and Name The name pingguite comes from its discovery locality – the Pinggu District near Beijing, China. The mineral was first described in 1994 by Shen Jinchuan and Li Wankui and approved by the International Mineralogical Association (IMA) under number IMA1992-035. ## Uses Pingguite has no industrial application. Its significance is purely scientific and for collectors.

Properties

Mohs hardness
2-3
Luster
Vitreous to Adamantine
Streak
Light yellow
Density
8.45
Cleavage
Perfect on {0001}
Fracture
Micaceous
Transparency
Transparent to Translucent
Crystal system
Trigonal

Diagnostic features

## Identification Characteristic features of pingguite include its canary-yellow color, occurrence as small, tabular crystals forming rosette aggregates, and its extreme rarity. Identification requires advanced analytical methods such as Raman spectroscopy or X-ray diffraction (XRD). ## Distinguishing from Similar Minerals It can be confused with other secondary, yellow bismuth minerals, such as bismutite or preisingerite. Distinguishing it with the naked eye is practically impossible and requires specialized laboratory equipment. Its occurrence in association with tellurium and bismuth in the oxidation zone is a key indicator. ## Crystal Forms Pingguite forms very thin, tabular crystals with a hexagonal outline, which often combine into rosettes, spherulites, or irregular aggregates.

Geological environment

## Genesis Pingguite is a secondary mineral, formed in the oxidation zones of hydrothermal, polymetallic ore veins rich in bismuth and tellurium. It forms as a result of the weathering of primary minerals containing these elements. ## Mineral Associations At its type locality (Pinggu, China), it co-occurs with native bismuth, native tellurium, gold, galena, pyrite, chalcopyrite, quartz, fluorite, barite, and other rare bismuth tellurites and tellurates, such as tellurite, paratellurite, schmitterite, and bismutite. ## Localities Apart from the type locality in Pinggu District, China, its occurrence has only been confirmed at the Wendy Mine in La Paz County, Arizona, USA. It is a mineral with an extremely limited number of known occurrences.

Rarity

Very rare

For collectors

## Quality Criteria The quality of a pingguite specimen is assessed based on the richness and size of the crystal aggregates on the rock matrix. The most desirable specimens are those with clearly formed, intensely yellow crystal rosettes, contrasting with the substrate. Due to the microscopic nature of the mineral, the aesthetics of the entire aggregate, rather than individual crystals, are crucial. ## Popular Localities The only source of specimens available on the collector's market is the type locality in Pinggu, China. Specimens from the Wendy Mine in Arizona are practically unavailable.

Care and storage

## Cleaning Pingguite specimens are extremely small and delicate. Any mechanical cleaning should be avoided. If absolutely necessary, compressed air can be used from a safe distance to remove dust. Contact with water or other chemicals is not recommended. ## What to Avoid Avoid contact with chemicals, especially acids, which can destroy the mineral. Specimens should be protected from vibrations, shocks, and direct physical contact. Due to its chemical composition, avoid inhaling dust and wash hands after contact. ## Storage The safest storage method is to keep the specimen in its original, sealed "micromount" box. This protects the mineral from dust, mechanical damage, and reduces the risk of losing microscopic crystals.

Sources

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