a dark-colored, hard, orthorhombic mineral, (Y,Ca,Ce,U,Th)(Nb,Ta,Ti)O, containing oxides of several chemical elements, esp. of calcium, uranium, titanium, and certain rare-earth elements
See euxenite in American Heritage Dictionary 4
(yo͞okˈsə-nītˌ)
noun
A lustrous, blackish-brown rare-earth mineral consisting primarily of cerium, erbium, titanium, uranium, and yttrium.