monazite

from WordNet (r) 3.0 (2006)

monazite
    n 1: a reddish-brown mineral containing rare earth metals; an
         important source of thorium and cerium

from The Collaborative International Dictionary of English v.0.48

Monazite \Mon"a*zite\ (m[o^]n"[.a]*z[imac]t), n. [From Gr.
   mona`zein to be solitary, in allusion to its isolated
   crystals.] (Min.)
   A mineral occurring usually in small isolated crystals, -- a
   phosphate of the cerium metals.
   [1913 Webster]