Monazite
Monazite, MON uh zyt, is a heavy, yellow-brown mineral. It is a compound of phosphates (phosphorus and oxygen) of the rare-earth metals and thorium. Monazite is one of the chief sources of thorium, a nuclear fuel used in some nuclear reactors. Monazite is also an important source for the rare-earth elements and compounds, used widely in glass and metal manufacturing.