The mineral
bastnäsite (or
bastnaesite) is one of a family of three
carbonate-
fluoride minerals, which includes bastnäsite-(
Ce) with a formula of (Ce, La)CO
3F, bastnäsite-(
La) with a formula of (La, Ce)CO
3F, and bastnäsite-(
Y) with a formula of (Y, Ce)CO
3F. Some of the bastnäsites contain OH- instead of F- and they 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 monazite are the two largest sources of cerium and other
rare earth elements.