Nordite-(Ce)

Chemical formula: Na₃Sr₂+Ce₃+Zn₂+Si₆O₁₇

A rare sodium, strontium, cerium, and zinc silicate, forming tabular or prismatic crystals of brown color and vitreous luster.

## Characteristics Nordite-(Ce) is a complex silicate belonging to the nordite group. It forms elongated, prismatic or tabular crystals, often with striated surfaces. It usually occurs as granular or radial aggregates. It is a brittle mineral, with a characteristic brown, reddish-brown, or yellowish-brown color. ## Physical properties This mineral is characterized by a hardness of 5-5.5 on the Mohs scale and a density of approximately 3.45 g/cm³. It has a vitreous luster and is translucent to opaque. It exhibits perfect cleavage in one direction. ## Colors and varieties Nordite-(Ce) occurs in shades of brown, from yellowish-brown through reddish-brown to dark brown. No named commercial or color varieties are distinguished. ## History and name The name "nordite" comes from the Norwegian word "nord" (north), referring to its occurrence in the northern part of the Kola Peninsula in Russia. The suffix "-(Ce)" in the name nordite-(Ce) indicates the dominance of cerium as a rare-earth element in its chemical composition. The mineral was first described by Waldemar Christopher Brøgger in 1901, although the original analysis did not include rare-earth elements, which were identified in later studies. ## Applications Nordite-(Ce) has no industrial applications. It is solely an object of interest for collectors of rare minerals and a subject of scientific research due to its complex crystal structure and chemical composition.

Properties

Mohs hardness: 5-5.5
Luster: Vitreous
Streak: White
Density: 3.45
Cleavage: Perfect on {100}
Fracture: Uneven
Transparency: Translucent to opaque
Crystal system: Orthorhombic

Diagnostic features

## Identification Nordite-(Ce) can be recognized by its characteristic prismatic or tabular crystal habit, brown color, vitreous luster, and perfect cleavage. It often occurs in alkaline pegmatites in association with other rare minerals. ## Distinguishing from similar minerals It can be confused with other brown silicates found in similar environments, such as eudialyte (usually more reddish or pinkish, with lower hardness) or lamprophyllite (often has a more metallic or bronze luster and a different crystal form). Accurate identification requires advanced analytical methods, such as X-ray diffraction (XRD) or chemical analysis (EDS). ## Crystal forms Nordite-(Ce) crystals are typically prismatic, elongated along one axis, or have a flattened tabular form. They often form radial or granular aggregates within the host rock.

Geological environment

## Genesis Nordite-(Ce) is an igneous mineral, crystallizing in the late stages from alkaline, silica-undersaturated melts. It occurs mainly in nepheline syenite pegmatites and in xenoliths within volcanic rocks. ## Mineral associations This mineral often co-occurs with other rare alkaline minerals, such as aegirine, nepheline, microcline, eudialyte, lorenzenite, lamprophyllite, murmanite, and lomonosovite. ## Localities The most important and classic localities for nordite-(Ce) are in Russia, in the alkaline massifs of the Kola Peninsula (Lovozero and Khibiny massifs). It is also known from the Ilímaussaq complex in Greenland and from Mont Saint-Hilaire in Quebec, Canada.

Rarity

Rare

For collectors

## Quality criteria The most highly valued specimens by collectors are those with well-formed, sharp, and undamaged crystals of intense, reddish-brown color. Contrast with a light host rock (e.g., nepheline or microcline) and co-occurrence with other rare minerals enhance their attractiveness. Large, single crystals or rich aggregates are much more desirable than small, embedded grains. ## Popular localities The best collector specimens come from the Lovozero massif on the Kola Peninsula in Russia. Specimens from Greenland and Mont Saint-Hilaire, although also valued, are usually smaller and less common on the market.

Care and storage

## Cleaning Nordite-(Ce) specimens should be cleaned very carefully, using a soft brush to remove dust. If necessary, distilled water can be used, but prolonged soaking should be avoided. Always thoroughly dry the specimen after cleaning. ## What to avoid The mineral is sensitive to acids, which can damage it. Contact with household and laboratory chemicals should be avoided. Due to its perfect cleavage, it is susceptible to mechanical damage and should be protected from impacts and falls. ## Storage Nordite-(Ce) specimens are best stored in separate, padded collector's boxes to prevent scratches and damage caused by contact with harder minerals. They should be protected from dust and sudden temperature changes.

Sources

IMA Mineral List (CNMNC)