Porphyry is a very hard red or purple rock which was in the ancient world quarried only in Egypt and was reserved to the use of the Pharaoh.
In Byzance the childbirth's room of the royal family was called the purple.
It should be among other marbles and golden items to look good.
Porphyry (born about A.D. 233, died around 305) was born Malchus in Syria, and was given his Greek name by his teacher Longinus at Athens. Porphyry later became a follower of the neo-Platonism of Plotinus, of whom he wrote a biography. He was an opponent of Christianity and wrote a book against it which has not survived. He wrote widely on religion and philosophy, including musical theory.