Zuolinite

Chemical formula: Ba₂Sr(Nb₅+₄.₅Fe₃+₀.₅)O₁₅

A very rare barium, strontium, niobium, and iron oxide discovered in the Chinese Bayan Obo rare-earth element deposit.

## Characteristics Zuolinite is a very rare oxide mineral, being a complex oxide of barium, strontium, niobium, and iron. It was approved by the International Mineralogical Association (IMA) in 2014. Due to its rarity, it occurs as microscopic grains that are not visible to the naked eye. ## Physical properties The mineral crystallizes in the tetragonal system. Due to the microscopic size of the crystals, its physical properties are difficult to observe macroscopically, and identification relies on structural and chemical studies. ## Colors and varieties No macroscopic color or gemological varieties of this mineral have been described. ## History and name Zuolinite was described and approved by the IMA under the number 2014-050. Its only confirmed locality is the Chinese Bayan Obo deposit, from which the holotype originates. ## Uses This mineral has no industrial application. It serves exclusively as a subject of crystallochemical and mineralogical research.

Properties

Crystal system: Tetragonal

Diagnostic features

## Identification Identification of zuolinite in the field or in a standard collection is impossible. It requires advanced analytical techniques such as X-ray diffraction (XRD) and micro-area chemical analysis using electron microscopy (SEM-EDS/WDS). ## Distinguishing from similar minerals Chemically, zuolinite can be confused with other rare niobates and oxides occurring in the Bayan Obo deposit. Definitive distinction requires confirmation of the crystal structure. ## Crystal habits It crystallizes in the tetragonal system, forming microscopic grains within the host rock.

Geological environment

## Genesis Zuolinite forms under specific geological conditions associated with the formation of giant rare-earth element, niobium, and iron deposits. ## Mineral associations It occurs in paragenesis with other rare minerals typical of the Bayan Obo deposit, including numerous niobates, carbonates, and silicates characteristic of this environment. ## Localities The only confirmed locality (locus typicus) is the Bayan Obo deposit in the Bayan Obo mining district, Baotou Prefecture (Inner Mongolia, China).

Rarity

Extremely rare

For collectors

## Quality criteria Zuolinite does not occur in the form of classic collector specimens. Only documented host rock samples from the Bayan Obo deposit confirmed by analytical testing have value. ## Popular localities The Bayan Obo deposit in China is the only known source of this mineral in the world.

Care and storage

## Cleaning Rock samples containing zuolinite should be cleaned using compressed air only. Ultrasonic cleaners and invasive mechanical methods, which could destroy microscopic grains, should be avoided. ## What to avoid Contact with any chemical reagents, including acids and bases that could react with the host rock, should be avoided. ## Storage Specimens are best stored in airtight micromount boxes in a dry environment, protected from dust and mechanical damage.

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External references

https://www.mindat.org/min-499359.html