Monazite
WordNet
noun
(1) A reddish-brown mineral containing rare earth metals; an important source of thorium and cerium
WiktionaryText
Noun
- any of a range of reddish-brown minerals that are mixed phosphates of the lighter rare earth elements lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium and yttrium