Porphyry (geology) - Historical and Cultural Uses

Historical and Cultural Uses

Pliny's Natural History affirmed that the "Imperial Porphyry" had been discovered at an isolated site in Egypt in AD 18, by a Roman legionary named Caius Cominius Leugas. It came from a single quarry in the Eastern Desert of Egypt, from 600 million year old andesite of the Arabian-Nubian Shield. The road from the quarry westward to Qena (Roman Maximianopolis) on the Nile, which Ptolemy put on his second-century map, was described first by Strabo, and it is to this day known as the Via Porphyrites, the Porphyry Road, its track marked by the hydreumata, or watering wells that made it viable in this utterly dry landscape. Porphyry was extensively used in Byzantine imperial monuments, for example in Hagia Sophia and in the "Porphyra", the official delivery room for use of pregnant Empresses in the Great Palace of Constantinople.

After the fourth century the quarry was lost to sight for many centuries. The scientific members of the French Expedition under Napoleon sought for it in vain, and it was only when the Eastern Desert was reopened for study under Muhammad Ali that the site was rediscovered by Burton and Wilkinson in 1823.

As early as 1850 BC on Crete in Minoan Knossos there were large column bases made of porphyry. All the porphyry columns in Rome, the red porphyry togas on busts of emperors, the porphyry panels in the revetment of the Pantheon, as well as the altars and vases and fountain basins reused in the Renaissance and dispersed as far as Kiev, all came from the one quarry at Mons Porpyritis ("Porphyry Mountain", the Arabic Jabal Abu Dukhan), which seems to have been worked intermittently between 29 and 335 AD.

Porphyry was used for the blocks of the Column of Constantine in Istanbul.