Source : Webster's Revised Unabridged Dictionary (1913)

Disthene \Dis"thene\, n. [Gr. di- = di`s- twice + ? force: cf.
   F. disth[`e]ne.] (Min.)
   Cyanite or kyanite; -- so called in allusion to its unequal
   hardness in two different directions. See {Cyanite}.