Source : Webster's Revised Unabridged Dictionary (1913)

Whinstone \Whin"stone"\, n. [Whin + stone; cf. Scot.
   quhynstane.]
   A provincial name given in England to basaltic rocks, and
   applied by miners to other kind of dark-colored unstratified
   rocks which resist the point of the pick. -- for example, to
   masses of chert. Whin-dikes, and whin-sills, are names
   sometimes given to veins or beds of basalt.

Source : WordNet®

whinstone
     n : any of various hard colored rocks (especially rocks
         consisting of chert or basalt) [syn: {whin}]