Rémondite-(Ce)

Chemical formula: Na₃(Ce³⁺,Ca,Na)₃(CO₃)₅

A rare sodium and cerium carbonate from the burbankite group, forming small, orange-red to brown crystals with a vitreous luster.

## Characteristics Rémondite-(Ce) is a complex sodium, cerium, and calcium carbonate belonging to the burbankite group. It occurs as small, well-formed, hexagonal crystals with prismatic or tabular habit. It typically forms radial aggregates or granular masses. It is a transparent to translucent mineral with a characteristic, intense color. ## Physical Properties This mineral is characterized by a hardness of 3-3.5 on the Mohs scale, making it relatively soft. Its density is approximately 3.43 g/cm³. It has a vitreous luster on crystal faces and a conchoidal fracture. ## Colors and Varieties The typical coloration of rémondite-(Ce) ranges from orange-red to brown. No distinct color varieties or commercial varieties have been identified. ## History and Name The mineral's name honors the French amateur mineralogist Guy Rémond (born 1933) for his contributions to the mineralogy of uranium deposits. The suffix "-(Ce)" indicates the dominant rare earth element in its composition – cerium. The mineral was first described in 1989 by Cesbron, Giraud, Pilleri, and Raul. ## Uses Due to its rarity and small crystal size, rémondite-(Ce) has no industrial applications. It is solely an object of interest for collectors specializing in rare minerals and for scientists.

Properties

Mohs hardness
3-3.5
Luster
Vitreous
Density
3.43
Fracture
Conchoidal
Transparency
Transparent,Translucent
Crystal system
Monoclinic

Diagnostic features

## Identification Characteristic features include: orange-red color, hexagonal crystal outline, vitreous luster, and relatively low hardness. It reacts vigorously with acids, which is typical for carbonates. ## Distinguishing from Similar Minerals It can be confused with other minerals from the burbankite group, from which differentiation requires advanced chemical analysis (EDS/WDS) to determine the dominant rare earth element. From other orange or brown minerals (e.g., some garnets, sphalerite), it is distinguished by its lower hardness and crystal form. ## Crystal Forms It forms hexagonal (in shape) prismatic crystals, often terminated by a pyramid or pinacoid. It also occurs as radial aggregates and granular masses.

Geological environment

## Genesis It is a hydrothermal mineral, associated with late stages of crystallization within alkaline igneous rocks, such as carbonatites and nephelinites. It forms in veins and mineral vugs cutting these rocks. ## Mineral Associations It often co-occurs with other rare alkaline minerals, such as ewaldite, mckelveyite-(Y), burbankite, calcynite, pyrite, as well as quartz and calcite. ## Localities The most important and type locality (locus typicus) is Eboundja in Cameroon. It is also known from the Mont Saint-Hilaire alkaline complex in Quebec (Canada), where it occurs as well-formed crystals.

Rarity

Very rare

For collectors

## Quality Criteria The most prized specimens are those with well-formed, sharp, transparent crystals of intense, orange-red color. Aesthetic composition on the rock matrix and association with other rare minerals are also important. Due to the small size of the crystals, even millimeter-sized specimens are considered valuable. ## Popular Localities Collectors primarily seek specimens from Mont Saint-Hilaire in Canada, which are considered the best in the world in terms of crystal quality and size. Specimens from the type locality in Cameroon are mainly of scientific interest.

Care and storage

## Cleaning Specimens should be cleaned very carefully, using a soft brush to remove dust. Brief rinsing in distilled water is permissible, followed by thorough drying. Ultrasonic cleaners should not be used. ## What to Avoid As a carbonate, it is sensitive to acids, which cause its rapid dissolution. Contact with all household and laboratory chemicals should be avoided. The mineral is soft and brittle, susceptible to scratches and mechanical damage. ## Storage It is recommended to store specimens in separate, padded collector's boxes to prevent abrasion and contact with harder minerals. It should be protected from dust and moisture.

External references

Sources

Read more