loparite

Loparite is a rare mineral species in the perovskite family of complex oxides. It is recognized as a solid-solution system with two principal varieties: loparite-(Ce), where cerium is the dominant rare-earth element, and loparite-(Nd), in which neodymium is the dominant rare-earth element. The composition generally includes rare-earth elements together with alkali metals such as sodium or cesium, and transition metals such as niobium and titanium, arranged in a perovskite-like lattice. The structure is typically described as a cubic or pseudo-cubic perovskite-related oxide, with large cations occupying the A-site and smaller transition metals occupying the B-site.

Occurrence and paragenesis: Loparite forms in alkaline igneous rocks, especially nepheline syenites and related carbonatites and pegmatites, where it occurs in association with other complex oxide minerals. It is best known from the Lovozero massif in the Kola Peninsula, Russia, where it can appear as coarse-grained crystals or in intergrowths with neighboring minerals such as nepheline, aegirine, and eudialyte. The mineral’s occurrence in such rocks makes it of interest to studies of alkaline magmatism and rare-earth mineralogy.

Mining and use: Loparite is not a major ore mineral for commercial production, but its rare-earth element content makes it of interest to mineralogists and petrologists. It serves as a record of the geochemical conditions in alkaline systems and contributes to the broader understanding of perovskite-like minerals in nature.

Etymology and history: The name and formal description of loparite reflect its characteristic occurrence in alkaline rocks and its placement within the perovskite oxide group.