Chemical composition: (Ce, La, Y, Th)(PO₄)

A widely occurring mineral containing metals of the rare-earth series. Monazite is a phosphate (containing a PO₄^3- group) of the radioactive elements, especially:

• thorium,
• cerium,
• lanthanum, and
• yttrium.

Although it is frequently referred to as a sand, it contains very little silica. It occurs in economically important amounts in Austsralia, India, South Africa, Brazil, and USA (Florida, North Carolina and Virgina).