Figure 3From: Brownish alterations on the marble statues in the church of Orsanmichele in Florence: what is their origin? Quattro Santi Coronati by Nanni di Banco ca.1409–1417. Polished cross section of the bronze-like patina showing the multiple layers of the patina. Visible illumination (a). Under it, the stone displays a particularly strong fluorescence. UV illumination (b).Back to article page