For thousands of years, porphyry has been renowned as a beautiful and durable paving and facing stone. A type of volcanic rock consisting of large-grained crystals such as feldspar or quartz, which is formed by a slow cooling process of igneous materials, the stone is valued for its aesthetically pleasing appearance. The term "porphyry" itself refers to the purplish red hues of the stone; in Latin, porphyry means purple.

Porphyry's chemical and mineral composition determine its high compression breaking point, resistance to chemical agents, and low "wearability." The stone is the most popular paver in Europe, and is favored for its flexibility in design, beauty, durability and low maintenance requirements. The stone is by far one of the most durable pavers in the world. In fact, porphyry has been used internationally to create popular projects, such as the Olympic stadium in Munich, Rodeo Drive in Los Angeles, the underground and market square in Paris, John F. Kennedy International Airport in New York and the military cemetery in Hawaii.

While porphyry has become a popular paver today, it was originally used for sarcophaguses, busts, vases and columns. The stone that was extracted in the Egyptian desert in the mountain Jebel Dhokan is known as Imperial Red porphyry or Ancient Red porphyry.

Aside from its beauty and durability, porphyry has been revered as a status symbol through the ages. Roman emperors were surrounded by the stone, born in rooms made of the porphyry and were sometimes even buried in sarcophaguses made of the stone. Today, it is highly regarded for both its functionality and beauty.

Quarries
With quarries found the world over, until recently, the stone was most commonly quarried in Italy, notably in Trentino. There, porphyry is characterized by felsic phenocrystals within a mass of red or pinkish gray color.

Legal issues related to the extraction of porphyry in Italy, along with the desire for a higher level of processed material, such as sawed, polished, semi-polished and flamed, have led to more recent quarrying outside of Europe. Quarry operators also have shown recent interest in the quarrying of porphyry blocks.

Mexican and Iranian porphyry typically display a deep red color, while Argentine porphyry includes diverse varieties, ranging from red to mauve to gray. In some areas of Argentina, the porphyry is quite compact, allowing for the extraction of regular blocks.

In Peru, an unusual type of porphyry, called Verde Esperanza, is quarried. This stone is characterized by a green color, which suggests the presence of chlorite. Verde Esperanza is mostly used as slabs, with the surface polished or flamed.

Colors
While the Latin name porphyry translates as "purple," its title can be quite deceptive. Porphyry is commonly known for its striking red and purple colors, but the stone can be found in shades of green, gray, gold, brown and black as well.

Red porphyry is often interspersed with small white spots, caused by feldspar and shorl deposits. Higher quantities of feldspar yield more transparent stones. When jasper enters its composition, porphyry is more opaque and highly colored.