whinstone

[hwin-stohn, win-] /ˈʰwɪnˌstoʊn, ˈwɪn-/
noun
1.
Chiefly British. any of the dark-colored, fine-grained rocks, especially igneous rocks, as dolerite and basalt.
Origin
1505-15; dial. (Scots and N England) whin whinstone (Middle English quin < ?) + stone
British Dictionary definitions for whinstone

whinstone

/ˈwɪnˌstəʊn/
noun
1.
any dark hard fine-grained rock, such as basalt
Word Origin
C16: from whin² + stone