This is what the entry from the Zecchi site looks like to help in ordering: “ BIANCO DI SAN GIOVANNI - (Cennino Cennini's original formula, for fresco painting) - Chemical composition: Lime White = Calcium Carbonate. .” Here is our best guess at the equivalent in Italian. This is from the Italian portion of the site: “ BIANCO DI SAN GIOVANNI - Formula originale "Cennino Cennini", per affresco - Composizione chimica: carbonato di calcio..”