Cebaite-(Ce)

Chemical formula: Ba<sub>3</sub>Ce<sup>3+</sup><sub>2</sub>(CO<sub>3</sub>)<sub>5</sub>F<sub>2</sub>

Cebaite-(Ce) is a rare carbonate mineral, distinguished by its characteristic waxy-yellow color and occurrence in the Bayan Obo deposit in China.

## Characteristics Cebaite-(Ce) is a complex barium and cerium carbonate with an admixture of fluorine. It forms small, tabular or short-prismatic crystals, which rarely exceed a few millimeters in length. Most often, it occurs as radial or spherulitic aggregates. Its most characteristic visual feature is its intense, waxy-yellow to yellow color and vitreous luster. ## Physical Properties This mineral is characterized by a hardness of 4.5-5 on the Mohs scale, placing it in the medium hardness range. Its density is approximately 4.31 g/cm³. It is transparent, and its streak is yellow-orange to light gray. It exhibits weak cleavage. ## Colors and Varieties Cebaite-(Ce) occurs in uniform shades, from light yellow to deep, waxy-yellow. No color or commercial varieties are distinguished. ## History and Name The mineral's name refers to its chemical composition - "Ce" from cerium and "ba" from barium. The suffix "-ite" is a standard mineral suffix. It was first described by Zhang Peishan and Tao Kejie in 1987. The type locality, from which the first described specimens originated, is the East Mine within the Bayan Obo deposit in China.

Properties

Mohs hardness
4.5-5
Luster
Vitreous
Streak
Yellow-orange to pale gray
Density
4.31
Cleavage
<mi>{30_1}</mi>
Fracture
Irregular/Uneven
Transparency
Transparent
Crystal system
Monoclinic

Diagnostic features

## Identification Cebaite-(Ce) can be identified by its characteristic waxy-yellow color, radial or spherulitic aggregates, and relatively high density. A key diagnostic feature is its violent reaction with hydrochloric acid, confirming its belonging to the carbonate group. ## Distinguishing from Similar Minerals It can be confused with other yellow carbonates from the oxidation zone, such as smithsonite or mimetite. However, it is distinguished by its specific aggregate form (radial aggregates), higher density, and co-occurrence with rare earth minerals in the specific geological environment of the Bayan Obo deposit. ## Crystal Forms Cebaite-(Ce) crystals are rare and usually appear as small, tabular forms. Much more often, it forms spherical, spherulitic aggregates or radial aggregates composed of tiny, acicular crystals.

Geological environment

## Genesis Cebaite-(Ce) is a mineral of hydrothermal origin. It forms in the late stages of mineralization processes, crystallizing in veins and vugs cutting dolomitic carbonate rocks. Its formation is associated with the activity of fluids rich in barium, fluorine, and rare earth elements. ## Mineral Associations This mineral co-occurs with other rare minerals from the Bayan Obo deposit, such as huanghoite-(Ce), cordylite-(Ce), bastnäsite-(Ce), parisite-(Ce), as well as with fluorite, barite, aegirine, and calcite. ## Localities The only confirmed and most important locality for cebaite-(Ce) in the world is its type locality – the Bayan Obo rare earth metal deposit in the Inner Mongolia Autonomous Region, China.

Rarity

Very rare

For collectors

## Quality Criteria The most prized specimens by collectors are those with well-formed, radial aggregates of intense, waxy-yellow color. The aesthetic composition with other contrasting associated minerals, such as purple fluorite, is also important. Due to the small size of the crystals, specimens with aggregate diameters exceeding one centimeter are considered exceptional. ## Popular Localities All global supply of collectible cebaite-(Ce) specimens comes from a single location – the Bayan Obo deposit in China. This is the only locality where this mineral occurs in quantities and quality suitable for specimen acquisition.

Care and storage

## Cleaning Cebaite-(Ce) specimens should only be cleaned mechanically, using a soft brush to remove dust. Due to its reactivity with acids, the use of water, especially with detergents, is not recommended. If liquid is necessary, use pure isopropyl alcohol and dry immediately. ## What to Avoid The mineral is sensitive to acids, which cause it to effervesce violently and decompose. Contact with all household and laboratory chemicals should be avoided. It should not be heated or exposed to sudden temperature changes. ## Storage Collectible cebaite-(Ce) specimens are best stored in closed, stable containers (so-called perky boxes) to protect them from dust, moisture, and mechanical damage. Due to its low hardness, it should not be stored in contact with harder minerals.

External references

Sources

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