Nero's bathtub - Imperial Porphyry

Nero's bathtub, a porphyry basin, was commissioned by Nero between 54-68 AD for his Domus Aurea (Golden House).

It was carved from a single, rare slab of Imperial porphyry from Egypt. Imperial Porphyry is a prized, deep purple, volcanic igneous rock with white feldspar crystals, quarried exclusively by the Romans in ancient Egypt at Mons Porphyrites (now Jabal Dokhan).

Red porphyry Sarcophagus of Helena, Musei Vaticani, Vatican City, Vatican.

Discovered around 18 AD by the Roman legionary Caius Cominius Leugas, in the remote desert, it became the most prestigious stone for the Roman and Byzantine elite. The name stems from the Greek word for purple. (porphyra) The stone was restricted solely to the Imperial family. Its rarity and exclusive ownership meant the stone was more valuable than gold.

At the center of the Pantheon in Rome is a large circle of Imperial porphyry on the floor where, for 300 years, new emperors stood to be crowned. Its immense value comes from the rarity of the purple porphyry and its historical connection to Roman imperial power. The quarry is now depleted, making the artifact irreplaceable. It is now located in the Pio Clementino Museum at the Vatican Museums in Rome.

The dense stone is hard, 6 to 7 on the Mohs scale. It was notoriously difficult to cut and shape, requiring months of labor by ancient artisans. Roman activity at Mons Porphyrites lasted almost without interruption until the 5th century.