whinstone, 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. [1913 Webster]