§ 4 Of Cipollaccio
Softer than serpentine is cipollaccio,30 a stone quarried in various places; it is of a crude yellowish green colour and has within it some square black marks, large and small, and also biggish white marks. Of this material one may see in various places columns both massive and slender, as well as doors and other ornaments, but not figures. There is a fountain of this stone in Rome in the Belvedere, that is to say a niche in a corner of the garden where are the statues of the Nile and of the Tiber;31 Pope Clement VII had this niche made, after a design by Michelagnolo,32 to adorn the statue of a river god that it might look very beautiful in this setting made in imitation of natural rocks, as indeed it actually does. Cipollaccio is also sawn into panels, round and oval, and into similar pieces which, when arranged with other stones in pavements and other flat surfaces, make lovely compositions. It takes a polish like porphyry and serpentine and is sawn in the same manner. Numberless pieces of it are found in Rome, buried under the ruins; these come to light daily and thus of ancient things modern works are made, such as doors and other ornamental details, which, wherever placed, are decorative and very beautiful.