Source : Webster's Revised Unabridged Dictionary (1913)

Schorl \Schorl\ (sh[^o]rl), n. [G. sch["o]rl; cf. Sw. sk["o]rl.]
   (Min.)
   Black tourmaline. [Written also {shorl}.]

Source : WordNet®

schorl
     n : black tourmaline