Source : Webster's Revised Unabridged Dictionary (1913)

Samarskite \Sa*mar"skite\, a. [After Samarski, a Russian.]
   (Min.)
   A rare mineral having a velvet-black color and submetallic
   luster. It is a niobate of uranium, iron, and the yttrium and
   cerium metals.

Source : WordNet®

samarskite
     n : a complex black mineral occuring in pegmatites