Flinty

It was late at night and frosty; high above them on the hills the cloppety clop, cloppety clop of a horse's hooves picking their way on the flinty stone track died away in the distance.

flinty rock

flinty slate

Public opinion has turned flintier in recent years on welfare spending.

While the texture of his playing was often flinty, his licks and leads were flush with feeling.