Biraite-(Ce)

Chemical formula: Ce<sup>3+</sup><sub>2</sub>Fe<sup>2+</sup>Si<sub>2</sub>O<sub>7</sub>(CO<sub>3</sub>)

Biraite-(Ce) is a very rare silicate group mineral, distinguished by a unique combination of cerium, iron, and a carbonate group in its structure.

## Characteristics Biraite-(Ce) is an extremely rare mineral belonging to the silicates. It forms very small, tabular or platy crystals, reaching sizes up to 0.2 x 0.1 x 0.03 mm. They usually occur as irregular aggregates or clusters. Due to the microscopic size of the crystals, its visual features are difficult to observe without specialized equipment. ## Physical Properties Biraite-(Ce) crystals exhibit a vitreous luster. This mineral is brittle. Its hardness and density have not been precisely measured due to the small amount of available material. ## Colors and Varieties Biraite-(Ce) has a color ranging from yellow to yellowish-brown. No varieties are known. ## History and Name The mineral's name comes from its discovery locality – the Bira Massif (Bira) in Khabarovsk Krai, Russia. The "-(Ce)" suffix refers to the dominant rare earth element in its composition, which is cerium. The mineral was officially approved by the International Mineralogical Association (IMA) in 2007 (IMA2007-028). It was described by Russian mineralogists I.O. Pekov, N.V. Chukanov, and others. ## Uses Biraite-(Ce) has no industrial applications. Its significance is purely scientific and as a collector's item, being a unique and rare mineral species.

Properties

Mohs hardness
4
Luster
Vitreous
Streak
Yellowish
Density
4.85
Cleavage
Good on {100}
Fracture
Uneven
Transparency
Translucent
Crystal system
Monoclinic

Diagnostic features

## Identification Identification of biraite-(Ce) is only possible using advanced analytical methods, such as Raman spectroscopy, X-ray diffraction (XRD), and chemical analysis (EDS/WDS). In field conditions or a typical collection, recognizing it "by eye" is impossible. Its characteristic feature is its occurrence in a specific geological environment – skarns. ## Distinguishing from Similar Minerals Due to its microscopic size and color, it can be confused with many other rare silicates found in skarns. Definitive differentiation requires specialized laboratory analysis. ## Crystal Forms Biraite-(Ce) forms very small, thin, tabular or platy crystals, often gathered in irregular aggregates. The crystals are too small to observe details of their structure with the naked eye.

Geological environment

## Genesis Biraite-(Ce) forms in skarns, which are metamorphic rocks created at the contact of magmatic intrusions (in this case, granites) with carbonate rocks (limestones). It is a product of metasomatic processes occurring at high temperatures. ## Mineral Associations This mineral coexists with other minerals typical of skarns, such as andradite (melanite variety), hedenbergite, wollastonite, microcline, titanite, fluorite, as well as rarer cerium minerals like bastnäsite-(Ce) and allanite-(Ce). ## Localities The only confirmed locality of biraite-(Ce) in the world is its type locality – the Bira iron deposit, in Khabarovsk Krai in the Russian Far East.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of a biraite-(Ce) specimen is primarily assessed based on the richness and quantity of the mineral itself on the rock matrix, as well as its association with other well-formed minerals. Since the crystals are microscopic, their individual form or color is less significant than the confirmed presence and abundance in a given cluster. The most valuable specimens are those with the highest concentration of yellow biraite-(Ce) aggregates on a contrasting background of the host rock. ## Popular Localities The only source of specimens is the type locality in Russia. Material from this location is extremely difficult to obtain and appears on the collector's market sporadically.

Care and storage

## Cleaning Due to its extreme rarity and fragility, biraite-(Ce) specimens should not be cleaned mechanically or chemically. Any contaminants are best left undisturbed. If absolutely necessary, compressed air can be used from a safe distance to remove loose dust. ## What to Avoid Avoid contact with all chemicals, including acids and bases, which can damage the mineral. It should be protected from ultrasound, high temperatures, and sudden thermal changes. Specimens are very brittle and susceptible to mechanical damage. ## Storage Biraite-(Ce) specimens should be stored exclusively in specialized, sealed "micromount" boxes to protect them from dust, humidity, and physical damage. Avoid exposure to direct sunlight.

Sources

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