Ferronordite-(Ce)

Chemical formula: Na<sub>3</sub>SrCe<sup>3+</sup>Fe<sup>2+</sup>Si<sub>6</sub>O<sub>17</sub>

Ferronordite-(Ce) is a rare silicate of sodium, strontium, cerium, and iron, forming tabular crystals of brown color and vitreous luster.

## Characteristics Ferronordite-(Ce) is a complex silicate belonging to the nordite group. It occurs as small, tabular or lath-like crystals, often forming radial or chaotic aggregates. Its characteristic features include a brown to reddish-brown color and a vitreous luster on crystal surfaces. ## Physical Properties This mineral has a hardness of approximately 5 on the Mohs scale. It exhibits a vitreous luster, and a greasy luster on fracture surfaces. It is a relatively dense mineral, with a density of about 3.45 g/cm³. It is brittle and shows an uneven fracture. ## Colors and Varieties Ferronordite-(Ce) occurs in shades of brown, from light brown through reddish-brown to dark brown. No distinct color varieties or commercial varieties are recognized. ## History and Name The name "ferronordite" refers to its chemical composition – the dominance of iron (ferro) over other elements in that structural position, and its kinship with the mineral nordite. The suffix -(Ce) indicates that cerium is the dominant rare earth element in its composition. The mineral was first described in 1997 by A.P. Khomyakov and co-workers based on material from the Lovozero Massif on the Kola Peninsula in Russia. ## Uses Ferronordite-(Ce) has no industrial applications. It is solely an object of interest for collectors specializing in rare minerals and scientists studying agpaitic pegmatites.

Properties

Mohs hardness
5
Luster
Vitreous, Greasy
Streak
Light brown
Density
3.45
Cleavage
Good on {100}
Fracture
Uneven
Transparency
Translucent to opaque
Crystal system
Orthorhombic

Diagnostic features

## Identification Ferronordite-(Ce) can be identified by its characteristic tabular or lath-like crystal habit, brown color, vitreous luster, and occurrence in a specific geological environment – nepheline-syenite pegmatites. ## Distinguishing from Similar Minerals It can be confused with other brown silicates found in the same environment, such as lorenzenite, eudialyte, or lamprophyllite. Differentiation requires analysis of crystal habit (ferronordite forms thin tablets), and definitive confirmation is only possible using advanced analytical methods (e.g., EDS/WDS). ## Crystal Forms Crystals are typically thin, tabular or lath-like, with a rectangular or hexagonal outline. They often form radial or irregular aggregates and intergrowths within the host rock.

Geological environment

## Genesis Ferronordite-(Ce) is a mineral of magmatic origin, crystallizing in the late stages of evolution of alkaline (agpaitic) pegmatites, associated with nepheline syenite intrusions. It forms in an environment highly saturated with alkaline elements (sodium) and rare earth elements. ## Mineral Associations This mineral co-occurs with other rare minerals of alkaline pegmatites, such as aegirine, microcline, nepheline, sodalite, eudialyte, lorenzenite, lamprophyllite, as well as minerals from the murmanite and lomonosovite groups. ## Localities The most important and classic localities for ferronordite-(Ce) are in Russia, on the Kola Peninsula, within the Lovozero (e.g., Mount Karnasurt, Alluaiv) and Khibiny alkaline massifs. These are the only confirmed occurrences of this mineral worldwide.

Rarity

Very rare

For collectors

## Quality Criteria Most valued by collectors are specimens with well-formed, sharp crystals of intense, reddish-brown color and distinct luster. Attractiveness is enhanced by a contrasting placement on a light rock matrix (e.g., on white nepheline or microcline) and co-occurrence with other rare minerals. Crystal size is also important, although they rarely exceed a few millimeters. ## Popular Localities The only source of collector specimens are the pegmatites of the Lovozero and Khibiny massifs on the Kola Peninsula in Russia. Specimens from these localities are the standard for this species.

Care and storage

## Cleaning Specimens should be cleaned only mechanically, using a soft brush to remove dust. Due to its rarity and potential reactivity, contact with water and chemical agents should be avoided. ## What to Avoid Avoid contact with acids and other chemicals that may damage the mineral's surface. It should not be heated or subjected to ultrasound. Prolonged exposure to strong sunlight is not recommended. ## Storage Ferronordite-(Ce) specimens are best stored under stable conditions, in closed collector boxes or display cases, to protect them from dust, moisture, and mechanical damage. Due to its brittleness, avoid placing it in contact with harder minerals.

Sources

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