Any of various hard sedimentary rocks which contain a high proportion of iron compounds; rock from which iron can be smelted, iron ore.

ore, esp. iron ore.

Originally Scottish and English regional. A kind of ironstone commonly found in globular concretions; a nodule of this; = cat-head, n. 2. Now rare.

A kind of ironstone. Also gubbin bat (bat, n.2 12), gubbin iron (gubbin stone).

Geology. Ironstone containing much clay. Also: clay rich in iron oxide. Frequently attributive.

a variety of ironstone.

A kind of ironstone occurring in nodules in the Shropshire coalfield.

= mine-stone n.

used attributively to denote a variety of ironstone.