This is what the entry from the Zecchi site looks like to help in ordering: “ Viridian Extrafine. Chemical composition: Ossido di Cromo idrato (Series: 13) .” Here is our best guess at the equivalent in Italian. This is from the Italian portion of the site: “ VERDE SMERALDO-EXTRAFINE. Composizione chimica: Ossido di Cromo idrato (Gruppo: 13).”