Perbøeite-(Ce)

Chemical formula: (CaCe³⁺₃)(Al₃Fe²⁺)(Si₂O₇)(SiO₄)₃O(OH)₂

Perbøeite-(Ce) is a rare, grayish-green silicate from the gatelite group, occurring as tabular crystals in nepheline syenite pegmatites.

## Characteristics Perbøeite-(Ce) is a complex silicate belonging to the gatelite group. It forms tabular, bladed crystals, often grouped into radial or fan-shaped aggregates. Typical specimens are grayish-green to very pale green and exhibit a vitreous luster. It is a transparent mineral, which, combined with its crystalline form, gives it a distinctive appearance. ## Physical Properties This mineral has a hardness ranging from 6-7 on the Mohs scale, making it relatively scratch-resistant. Its density is approximately 4.47 g/cm³. It possesses good cleavage in one direction, which may be visible on some specimens. The luster is vitreous. ## Colors and Varieties Perbøeite-(Ce) occurs in shades of green, most commonly grayish-green or very light, pale green. No distinct color varieties or commercial varieties have been identified. ## History and Name The mineral's name honors the Norwegian mineral collector, Perbøe Larsen (born 1958), for his contributions to the study of pegmatites in the Langesundsfjorden and Tysfjorden areas of Norway. The -(Ce) suffix in the name indicates cerium as the dominant rare earth element in its chemical composition. The mineral was approved by the IMA in 2009. ## Applications Due to its rarity, Perbøeite-(Ce) has no industrial applications. It is solely an object of interest for collectors specializing in rare minerals and mineralogical systematics.

Properties

Mohs hardness
6-7
Luster
Vitreous
Streak
white
Density
4.474
Cleavage
{100} good, {001} imperfect
Fracture
Irregular/Uneven
Transparency
Transparent
Crystal system
Monoclinic

Diagnostic features

## Identification Perbøeite-(Ce) can be identified by its characteristic grayish-green color, tabular crystal form, often forming radial aggregates, and vitreous luster. Its occurrence in a specific geological environment (nepheline syenite pegmatites) is a key indicator. ## Distinguishing from Similar Minerals It can be confused with other silicates from the epidote or gatelite group. Final distinction from very similar minerals, such as ferriallanite-(Ce) or gatelite-(Ce), requires advanced analytical methods, such as spectroscopy or chemical analysis, to determine the exact composition and dominant elements. ## Crystal Forms Crystals are typically tabular or bladed, flattened along one of the axes. They often occur as radial or fan-shaped aggregates, where individual crystals radiate from a single point.

Geological environment

## Genesis It is an igneous mineral, crystallizing in the late stages of nepheline syenite pegmatite formation. It forms in an environment rich in rare earth elements, aluminum, calcium, and iron. ## Mineral Associations Perbøeite-(Ce) co-occurs with other minerals typical of nepheline syenite pegmatites, such as nepheline, albite, microcline, aegirine, zircon, titanite, mosandrite-(Ce), and various minerals from the epidote group. ## Localities The most important and typical localities for this mineral are in Norway, in the Nordland region. It has been described from the Hundholmen and Stetind sites in Narvik municipality and from Nedre Eivollen in Hamarøy municipality. These are the only confirmed occurrences worldwide.

Rarity

Very rare

For collectors

## Quality Criteria Specimens with well-formed, sharp crystals of distinct tabular form are most valued by collectors. Radial aggregates, where individual crystals are clearly visible and undamaged, enhance their appeal. The intensity and purity of the greenish color and the absence of mechanical damage are also important. ## Popular Localities All known collector specimens come from several localities in the Tysfjorden area of Nordland county in Norway. Specimens from the type localities (Hundholmen, Stetind, Nedre Eivollen) are most desired by specialists.

Care and storage

## Cleaning 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 Avoid contact with acids and strong chemicals, which can damage the mineral's surface. Due to the presence of cleavage, protect it from impacts and sudden temperature changes. ## Storage It is recommended to store specimens in separate, padded collector's boxes to prevent abrasions and mechanical damage. Protect it from dust and moisture.

External references

Sources

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