The mineral bastnäsite (or bastnaesite) is one of a family of three carbonate minerals, which includes bastnäsite-(Ce ) with a formula of (La, Ce)CO3F, and bastnäsite-(Y) with a formula of (Y, Ce)CO3F. Some of the bastnäsites contain OH− instead of F− and receive the name of hydroxylbastnasite. Most bastnäsite is bastnäsite-(Ce), and cerium is by far the most common of the rare earths in this class of minerals. Bastnäsite and the phosphate mineral are the two largest sources of cerium and other rare-earth elements.
Bastnäsite was first described by the Swedish chemist Wilhelm Hisinger mine near Riddarhyttan , Sweden Bastnäsite also occurs as very high-quality specimens at the Zagi Mountains, Pakistan. Bastnäsite occurs in alkali granite and in associated pegmatites and in associated fenites