1769 W. Sharp iv. 64 A very hard stone, called rock flint stone.
1811 J. Pinkerton I. ii. ii. 154 Bluish grey rock-flint, sometimes mamellated, and approaching to chalcedony, from the lead-mines of Bretagne.
1996 (Nexis) Jan. 39 Sand flint, rock flint and tripoli flint (generally called potters flint) are various types of ground sandstone and quartzite.