Christofschäferite-(Ce)

Chemical formula: (Ce₃+,La₃+,Ca)₄Mn₂+(Ti₄+,Fe₃+)₃(Fe₃+,Fe₂+,Ti₄+)(Si₂O₇)₂O₈

Christofschäferite-(Ce) is a very rare mineral from the czochralskiite group, forming tiny, black crystals in lavas of the Bellerberg volcano in Germany.

## Characteristics Christofschäferite-(Ce) is an extremely rare mineral belonging to the czochralskiite group. It occurs as very small, tabular or lath-like crystals, reaching up to 0.2 mm in size. The crystals are black and opaque, often forming aggregates or appearing as single flakes within the host rock. Due to their microscopic size, visual features are difficult to observe without specialized equipment. ## Physical Properties The mineral is characterized by a Mohs hardness of approximately 5.5. It has a metallic to submetallic luster. It is brittle, and its density, calculated based on the chemical formula and unit cell parameters, is 4.88 g/cm³. The crystals exhibit perfect cleavage in one direction. ## Colors and Varieties Christofschäferite-(Ce) is a mineral of uniform, black color. No color varieties or commercial varieties are known. ## History and Name The mineral was discovered in rock samples from the Bellerberg volcano in the Eifel mountains, Germany. It was approved by the International Mineralogical Association (IMA) in 2015 under number IMA2015-080. The name honors Christof Schäfer (born 1960), a German mineral collector who specializes in minerals from the Eifel region and was the first to find this mineral. ## Uses Christofschäferite-(Ce) has no industrial application. Its significance is purely scientific and as a collector's item, as a unique and rare representative of its mineralogical group.

Properties

Mohs hardness: 5.5
Luster: Metallic to submetallic
Streak: Black
Density: 4.88
Cleavage: Perfect on {001}
Fracture: Uneven
Transparency: Opaque
Crystal system: Monoclinic

Diagnostic features

## Identification Identification of Christofschäferite-(Ce) is almost exclusively possible using advanced laboratory methods, such as energy-dispersive spectroscopy (EDS/EDX) for chemical composition analysis and X-ray diffraction (XRD) to determine the crystal structure. Visually, in collector's conditions, identification relies on trust in the label and knowledge of the locality. Characteristic features include its black color, metallic luster, and occurrence as tiny flakes in the specific geological environment of the Bellerberg volcano. ## Distinguishing from Similar Minerals It can be confused with other black, platy minerals found in the same environment, such as hematite, ilmenite, or other minerals from the czochralskiite group. Definitive differentiation requires chemical analysis, which will reveal the unique combination of cerium, manganese, and titanium. ## Crystal Forms Crystals are very small, usually not exceeding 0.2 mm. They take the form of thin, tabular or lath-like flakes, often with a hexagonal outline. They occur individually or form small, rosette-like aggregates.

Geological environment

## Genesis Christofschäferite-(Ce) forms under volcanic conditions, within xenoliths (fragments of foreign rocks) in leucite-tephrite lavas. It is a mineral that crystallizes at high temperatures from the gas phase in voids and fissures within these rocks. ## Mineral Associations This mineral co-occurs with sanidine, diopside, hematite, magnetite, nepheline, leucite, apatite, as well as other rare titanium minerals such as sharyginite and delhuyarite-(Ce). ## Localities The only confirmed locality (type locality) of Christofschäferite-(Ce) in the world is the Caspar quarry on the Bellerberg volcano, near the town of Mayen, in the Eifel region, Rhineland-Palatinate, Germany.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of Christofschäferite-(Ce) specimens is primarily assessed based on the abundance and development of microscopic crystals on the rock matrix. Specimens with numerous, sharply defined crystals with a distinct luster are most highly valued. The size of individual crystals, even if it is a fraction of a millimeter, is crucial. Contrast with a light host rock (e.g., sanidine) also enhances the visual appeal of the specimen. ## Popular Localities The only source of specimens is the type locality - the Caspar quarry on the Bellerberg volcano in Germany. All specimens available on the collector's market originate from this single location.

Care and storage

## Cleaning Specimens of Christofschäferite-(Ce) are extremely delicate due to the microscopic size of the crystals. Mechanical cleaning is not recommended. If necessary, compressed air (from a safe distance) can be used to remove loose dust. Avoid contact with water and any chemicals. ## What to Avoid Ultrasonic cleaners, strong water jets, acids, solvents, and all chemical agents should be absolutely avoided. The mineral is brittle, so it should be protected from impacts, scratches, and vibrations. It should not be heated or exposed to sudden temperature changes. ## Storage Specimens should be stored exclusively in specialized, sealed "micromount" boxes that protect them from dust, mechanical damage, and moisture. Store in stable room conditions, away from direct sunlight and heat sources.

Sources

IMA Mineral List (CNMNC)