§ 50 The Tools and Materials Used in Marble Carving
Sculptors are accustomed, in working their marble statues, to begin by roughing out the figures with a kind of tool they call ‘subbia,’ which is pointed and heavy; it is used to block out their stone in the large, and then with other tools called ‘calcagnuoli’ which have a notch in the middle and are short, they proceed to round it, till they come to use a flat tool more slender than the calcagnuolo, which has two notches and is called ‘gradina’: with this they go all over the figure, gently chiselling it to keep the proportion of the muscles and the folds, and treating it in such a manner that the notches or teeth of the tool give the stone a wonderful grace. This done, they remove the tooth marks with a smooth chisel, and in order to perfect the figure, wishing to add sweetness, softness and finish to it, they work off with curved files all traces of the gradina. They proceed in the same way with slender files and straight rasps, to complete the smoothing process,163 and lastly with points of pumice stone they rub all over the figure to give that flesh-like appearance that is seen in marvellous works of sculpture. Tripoli earth is also used to make it lustrous and polished, and for the same reason it is rubbed over with straw made into bunches—till, finished and shining, it appears before us in its beauty.164