Bainbridgeite-(NdCe)

Chemical formula: Na<sub>2</sub>Ba<sub>2</sub>NdCe<sup>3+</sup>(CO<sub>3</sub>)<sub>6</sub>·3H<sub>2</sub>O

Bainbridgeite-(NdCe) is a newly discovered, extremely rare mineral from the carbonate group, forming pink, hexagonal crystals in the Canadian Mont Saint-Hilaire quarry.

## Characteristics Bainbridgeite-(NdCe) is a hydrated carbonate of sodium, barium, and rare earth elements, belonging to the burbankite group. This mineral forms small, hexagonal, prismatic crystals, usually less than 1 mm in length. It occurs as single, well-formed crystals or small aggregates. Its unique chemical composition, with dominant neodymium and cerium, makes it an interesting subject for scientific research. ## Physical Properties Bainbridgeite-(NdCe) crystals exhibit a vitreous luster. They are brittle, and their fracture is conchoidal. The mineral's hardness on the Mohs scale is approximately 3-4, and its density has been calculated at 3.83 g/cm³. It is a relatively soft and light mineral. ## Colors and Varieties This mineral is characterized by a pale, pinkish-purple color. No pleochroism has been observed. As yet, no varieties have been distinguished. ## History and Name Bainbridgeite-(NdCe) was officially recognized as a new mineral species by the International Mineralogical Association (IMA) in 2022 (IMA2022-085). Its name honors John Bainbridge

Properties

Mohs hardness
3-4
Luster
Vitreous
Streak
White
Density
3.83
Cleavage
Imperfect on {0001}
Fracture
Conchoidal
Transparency
Transparent to translucent
Crystal system
Hexagonal

Diagnostic features

## Identification In practice, the identification of bainbridgeite-(NdCe) relies mainly on knowing its origin – the Mont Saint-Hilaire quarry. Its characteristic pale pink color, hexagonal crystal form, and co-occurrence with other rare alkaline minerals are distinctive. Due to the microscopic size of the crystals, final confirmation requires advanced analytical methods, such as Raman spectroscopy or EDS analysis. ## Distinguishing from Similar Minerals It can be confused with other pink or purple minerals from Mont Saint-Hilaire, such as rhodochrosite or some eudialytes. Bainbridgeite-(NdCe) differs from them by its crystal form (hexagonal prisms) and its lack of reaction with cold hydrochloric acid, unlike rhodochrosite. Final differentiation is only possible under laboratory conditions. ## Crystal Forms This mineral forms simple, six-sided (hexagonal) prismatic crystals, terminated by flat pinacoids. The crystals are usually small, not exceeding 1 mm in length.

Geological environment

## Genesis Bainbridgeite-(NdCe) forms in the late stages of hydrothermal processes within nepheline syenites and associated pegmatites. It crystallizes in rock cavities and fissures from solutions rich in sodium, barium, carbonates, and rare earth elements. ## Mineral Associations This mineral occurs in association with other rare minerals typical of the Mont Saint-Hilaire locality. It most commonly co-occurs with microcline, aegirine, rhodochrosite, ancylite-(Ce), petersenite-(Ce), and mckelveyite-(Y). ## Localities The only confirmed occurrence (type locality) of bainbridgeite-(NdCe) in the world is the Poudrette quarry in Mont Saint-Hilaire, Montérégie region, Quebec province, Canada. This is one of the world's most famous mineralogical localities, known for over 400 different mineral species.

Rarity

Extremely rare

For collectors

## Quality Criteria Due to its extreme rarity and microscopic size, the main criterion for collectible value is the mere confirmation of the mineral's presence on a specimen. Microcrystals with the best possible formation, intense pink coloration, and transparency are most highly prized. It is also important for the crystal to be isolated and clearly visible against a contrasting background (matrix), for example, on white microcline. Specimens with several crystals or in association with other rare minerals are particularly sought after. ## Popular Localities All collector specimens come from a single location in the world – the Poudrette quarry in Mont Saint-Hilaire, Canada. This is the only known locality for this mineral.

Care and storage

## Cleaning Due to the mineral's fragility and rarity, mechanical cleaning is highly inadvisable. If necessary, compressed air can be used to remove loose dust. Avoid contact with water and any chemical agents. ## What to Avoid Absolutely avoid contact with acids, which can damage it. The mineral is brittle, so it must be protected from impacts and scratches. It should not be heated or subjected to ultrasound. ## Storage Specimens of bainbridgeite-(NdCe) are extremely valuable and sensitive. They should be stored in stable conditions, in separate, padded collector boxes, away from light, moisture, and sudden temperature changes. It is best to keep them in their original "perky box" type packaging, in which they are usually sold.

Sources

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