Red porphyry is one of the most important stone materials of antiquity. The Romans called ii “Lapis porphyrites” due to its purple hue. Under Emperor Tiberius it became the stone used for imperial portraitsand sarcophagi, thus marking the life of emperors from birth until death. This material, highly appreciated inarchitecture and art, came from the eastern Egyptian desert and its use dates back to the Ptolemaic age (3rdcentury BC). From a geological point of view, it is a magmatic rock resulting from the solidification of lava during the Palaeozoic, about 600 million years ago.