§ 14 Of Peperino91
We shall also refer in a future chapter to a stone named piperno or more commonly peperigno, a blackish and spongy stone, resembling travertine, which is excavated in the Roman Campagna. It is used for the posts of windows and doors in various places, notably at Naples and in Rome; and it also serves artists for painting on in oil, as we shall relate in the proper place. This is a very thirsty stone and indeed more like cinder than anything else.