Iron pyrites, formerly used for striking fire; also, a flint.
2.
A stone which will bear the heat of a furnace without injury; especially applied to the sandstone at the top of the upper greensand in the south of England, used for lining kilns and furnaces.
... series. The higher portion of the Chloritic series in some districts has been called chloritic marl, from its consisting of a chalky marl with chloritic grains. In parts of Surrey, where calcareous matter is largely intermixed with sand, it forms a stone called malm-rock or firestone. In the cliffs of the southern coast of the Isle of Wight it contains bands of calcareous limestone with ... — The Student's Elements of Geology • Sir Charles Lyell Read full book for free!