cerianite

Cerianite is a rare oxide mineral whose principal constituent is cerium in the tetravalent state. Its chemical formula is CeO2, and it is regarded as the natural oxide form of cerium(IV) oxide. The mineral crystallizes in the cubic system and typically exhibits a fluorite-type structure. In mineral nomenclature, cerianite-(Ce) is used to indicate cerium as the dominant rare-earth element in the mineral.

Cerianite is uncommon in nature and is predominantly found in oxidation zones of rare-earth enriched ore deposits and in hydrothermal environments. It often occurs as small grains or as fine, anhedral crystals and can be associated with other rare-earth minerals such as xenotime, monazite, bastnäsite, parisite, and apatite. The color is variable, ranging from pale to dark, and the luster is generally vitreous to metallic.

The mineral was named to reflect its cerium content, with the suffix cerianite-(Ce) signaling cerium as the essential element. It is one of the few minerals whose essential component is CeO2, making it of particular interest to collectors and researchers studying rare-earth mineralogy. Notable occurrences have been reported from a limited number of localities worldwide, typically in geologic settings that concentrate rare-earth elements.

In summary, cerianite is a rare cubic oxide mineral representing natural CeO2, valued for its mineralogical significance and its status as a primary cerium oxide mineral in the Earth’s crust.