Near London, "rag-stone" often means Kentish ragstone, a material from the neighbourhood of Maidstone.
Ragstone, a dull grey stone, is still quarried on an industrial scale close to the Kent Downs AONB.
It has traditionally been used within the AONB as a road stone, cobble or sett and a walling block.
Due to its irregular shape, as with flint, ragstone has been set within brick quoins and bands.
Spalls, fist-sized irregular chips of ragstone, have been used to surface paths but modern usage of ragstone is as a general construction aggregate, including fill for gabions and loose or partly binding gravels.