Anzaite-(Ce)

Chemical formula: Ce<sup>3+</sup><sub>4</sub>Fe<sup>2+</sup>Ti<sup>4+</sup><sub>6</sub>O<sub>18</sub>(OH)<sub>2</sub>

Anzaite-(Ce) is a very rare, black oxide mineral of the crichtonite group, found in ultrabasic alkaline rocks.

## Characteristics Anzaite-(Ce) is an extremely rare mineral belonging to the crichtonite group. It forms very small, tabular or prismatic crystals, usually not exceeding 0.3 mm in size. It is observed as inclusions in other minerals, mainly in ilmenite. It has a black color and an opaque nature. ## Physical Properties This mineral is characterized by a metallic luster and a black streak. Its Mohs hardness ranges from 6 to 7, and its density, calculated from the chemical formula, is approximately 5.45 g/cm³. Due to the small size of the crystals, many physical properties are difficult to measure precisely. ## History and Name The mineral's name refers to its chemical composition, with dominant cerium (Ce), and honors Anwar Anz, a Russian geologist and researcher of titanium deposits. It was officially recognized by the International Mineralogical Association (IMA) in 2011 (IMA2011-060).

Properties

Mohs hardness
6-7
Luster
Metallic
Streak
Black
Density
5.45
Cleavage
None
Fracture
Uneven
Transparency
Opaque
Crystal system
Trigonal

Diagnostic features

## Identification Identification of anzaite-(Ce) is possible only through advanced laboratory methods, such as electron microprobe (EDS/WDS) for chemical composition analysis and X-ray diffraction (XRD) for crystal structure determination. Macroscopic visual identification is impossible. ## Distinguishing from Similar Minerals It can be confused with other black, opaque minerals of the crichtonite group, such as crichtonite, lindsleyite, or senaite, as well as with ilmenite, in which it often occurs. Differences can only be determined by precise chemical analysis, which will reveal a unique combination of cerium, iron, and titanium. ## Crystal Forms It forms hexagonal, tabular or short prismatic crystals up to 300 micrometers in size.

Geological environment

## Genesis Anzaite-(Ce) forms in ultrabasic alkaline rocks, particularly in carbonatites. It is a mineral of the late magmatic crystallization stage under these specific geochemical conditions. ## Mineral Associations This mineral occurs in close association with ilmenite (often as inclusions within it), as well as with calcite, dolomite, phlogopite, pyrochlore, zircon, and baddeleyite. ## Localities The only confirmed occurrence (type locality) of anzaite-(Ce) is the Afrikanda massif, located on the Kola Peninsula in the Murmansk Oblast, Russia.

Rarity

Extremely rare

For collectors

## Quality Criteria As a microscopic mineral, anzaite-(Ce) is not evaluated according to typical aesthetic criteria such as color or luster. Its collector and scientific value depends solely on the confirmation of its identity through chemical analysis and on the quality and richness of the mineral association on the host specimen. The most valuable specimens are those with clearly visible crystals under a microscope and analytically confirmed composition.

Care and storage

## Cleaning Due to its extreme rarity and microscopic size, anzaite-(Ce) specimens (usually as inclusions in ilmenite) should not be cleaned mechanically or chemically by collectors. Any cleaning should be left to specialists under laboratory conditions. ## What to Avoid Contact with any chemicals, ultrasound, and extreme temperature changes should be avoided. The mineral is stable, but its scientific and collector value requires maximum caution. ## Storage Specimens should be stored in stable conditions, in specialized "micromount" boxes, protecting them from dust, moisture, and mechanical damage. Exposure to direct sunlight should be avoided.

External references

Sources

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