Thorite

from WordNet (r) 3.0 (2006)

thorite
    n 1: a radioactive mineral consisting of thorium silicate; it is
         a source of thorium that is found in coarse granite

from The Collaborative International Dictionary of English v.0.48

Thorite \Tho"rite\, n. [So called by Berzelius from the
   Scandinavian god Thor. See {Thor}.] (Min.)
   A mineral of a brown to black color, or, as in the variety
   orangite, orange-yellow. It is essentially a silicate of
   thorium.
   [1913 Webster]