A rare mineral that incorporates the light rare-earth elements (lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium) and also yttrium. Monazite has a general formula of (La,Ce,Nd)PO₄, but Pr, Sm, Eu, Gd, and Y substitute for La, Ce, and Nd in solid solution in minor amounts. The dominant rare-earth element in a particular monazite is denoted by the atomic suffix, such as monazite-(Ce) in which cerium exists in amounts greater than other rare-earth atoms. Monazite-(Ce), monazite-(La), and monazite-(Nd) are officially recognized by the International Mineralogical Association.