The main ore of mercury is cinnabar, long used as a pigment by painters. He says that the colour is similar to "scolecium", probably the kermes insect. The dust is very toxic, so workers handling the material wear face masks of bladder skin. Copper and bronze are, says Pliny, most famous for their use in statues including colossi, gigantic statues as tall as towers, the most famous being the Colossus of Rhodes. He personally saw the massive statue of Nero in Rome, which was removed after the emperor's death. The face of the statue was modified shortly after Nero's death during Vespasian's reign, to make it a statue of Sol. Hadrian moved it, with the help of the architect Decrianus and 24 elephants, to a position next to the Flavian Amphitheatre (now called the Colosseum).