quarry tile
noun1
A very hard ceramic tile used e.g. as flooring, usually 1/2 to 3/4 inches (13 to 19 mm) in thickness, made by the extrusion process from natural clays or shales.
- The public areas have blue quarry-tile floors, pale blue glass mosaic walls and pillars and varnished timber ceilings; [...].1960 September, M. J. Wilson, “Harlow Town station opened”, in Trains Illustrated, page 542: