Cebaite-(Nd)

Chemical formula: Ba₃(Nd,Ce)₂(CO₃)₅F₂

A rare barium and neodymium carbonate, forming small, tabular crystals with a vitreous or pearly luster.

## Characteristics Cebaite-(Nd) is a rare mineral from the carbonate group, belonging to the cebaite series, in which neodymium (Nd) dominates the rare earth element position. It occurs as very small, tabular or bladed crystals, which rarely exceed 1 mm in length. Crystals are often gathered in rosette-like or radial aggregates. Due to their small size, its visual features are difficult to observe without magnification. ## Physical Properties The mineral is characterized by a hardness in the range of 4.5-5 on the Mohs scale. It has a vitreous to pearly luster, especially visible on cleavage planes. It is a relatively dense mineral, with a calculated density of approximately 4.85 g/cm³. Crystals are usually transparent to translucent. ## Colors and Varieties Cebaite-(Nd) is usually colorless, white, pale pink, or light purple. Its color is directly related to the presence of neodymium. No named varieties of this mineral are distinguished. ## History and Name The mineral's name refers to its chemical composition and structural similarity to cebaite-(Ce). The suffix "-(Nd)" indicates the dominance of neodymium among rare earth elements. It was first described by P. Zhang and K. Tao in 1987 based on material from the Bayan Obo iron and rare earth element mine in China.

Properties

Mohs hardness
4.5-5
Luster
Vitreous , Waxy
Streak
White
Density
0
Cleavage
Good on {001}
Fracture
Uneven
Transparency
Transparent to translucent
Crystal system
Monoclinic

Diagnostic features

## Identification Field identification of cebaite-(Nd) is practically impossible due to its rarity and small crystal size. In a collection, it can be recognized by its characteristic, small, tabular crystals forming rosette-like aggregates on a typical rock matrix from Bayan Obo. It reacts with hydrochloric acid. ## Distinguishing from Similar Minerals It can be confused with other rare earth element carbonates, such as cebaite-(Ce), cordylite-(Ce), parisite, or bastnäsite. Final differentiation requires advanced analytical methods, such as energy-dispersive spectroscopy (EDS/WDS) to confirm the dominance of neodymium over other rare earth elements. ## Crystal Forms It forms thin, tabular crystals with a hexagonal outline, often elongated and bladed. These crystals combine into radial or rosette-like aggregates, as well as fan-shaped forms.

Geological environment

## Genesis Cebaite-(Nd) forms in hydrothermal processes associated with carbonatites. It occurs in calcite-fluorite veins cutting through iron and rare earth element ore deposits. ## Mineral Associations It most commonly co-occurs with minerals such as: calcite, fluorite, barite, aegirine, riebeckite, as well as other rare earth element minerals, e.g., cebaite-(Ce), cordylite-(Ce), huanghoite-(Ce), and aeschynite-(Nd). ## Localities The only confirmed and well-documented locality for cebaite-(Nd) in the world is its type locality – the Bayan Obo iron and rare earth element deposit, in Inner Mongolia, China.

Rarity

Very rare

For collectors

## Quality Criteria The most prized specimens are those with well-formed, sharply terminated crystals forming aesthetic, rosette-like aggregates. Crystal size is also important – the larger the crystals, the more valuable the specimen. A contrasting rock matrix, for example with dark aegirine, enhances the visual appeal of the specimen. Purity and intensity of color (pink or purple) are also significant factors. ## Popular Localities All collector specimens of cebaite-(Nd) come from a single locality in the world: the Bayan Obo deposit in China. This is the only locality from which this mineral has been obtained in a quality suitable for specimen preparation.

Care and storage

## Cleaning Specimens should only be cleaned with compressed air to remove dust. Due to the small size of the crystals and their fragility, avoid contact with water and brushes, which could damage them or wash them out of the rock matrix. ## What to Avoid The mineral is sensitive to acids, which cause its rapid dissolution with the release of carbon dioxide. Ultrasonic cleaners and all chemicals should be avoided. Store away from moisture and extreme temperatures. ## Storage It is recommended to store specimens in closed, stable containers (e.g., "micromount" boxes) to protect them from dust, mechanical damage, and sudden changes in humidity. Exposure to strong light is not advisable, although there is no evidence of fading.

External references

Sources

Read more