Pentelic marble

How does it form?

Like other marbles, Pentelic marble formed by the metamorphism of limestone: layers of calcium carbonate laid down in the sea were buried deep during mountain building and recrystallised under heat and pressure without melting. In this marble, however, metamorphism did not wipe out every trace of the original rock: occasional fossil fragments turned to calcite can still be seen. The small amounts of quartz, white mica (muscovite), pyrite and apatite it contains come from impurities in the old limestone.

The grains of the marble have a clear orientation, so its strength depends on whether a load comes parallel or perpendicular to them. Its porosity is very low: even after natural weathering it is only about 0.3–0.7% at the surface.

What is it used for?

• The Acropolis: the buildings of ancient Athens, especially the monuments of the Acropolis, were built of Pentelic marble. Work on the Parthenon began in 447 BC and the building was substantially complete by 432 BC, with decoration continuing until at least 431 BC.
• Sculpture: the Parthenon’s frieze and pediment sculptures were carved from it. Isotope analyses have shown that the Elgin Marbles, now in the British Museum, came from one particular unit of the Pentelic quarries.
• Rome: the marble was also shipped to Rome, where it was used in buildings and sculpture.
• Stadium: the Panathenaic Stadium in Athens was built of Pentelic marble both in the 2nd century AD and before the 1896 Olympics.
• Restoration: today the ancient quarry supplies stone only for the Acropolis Restoration Project.

The quarries

The ancient quarries lie on the south-west slope of Mount Pentelicus, some 18 km north-east of Athens. The best known is the Spilia quarry, at about 700 metres, with Davelis Cave inside it. Chisel and wedge marks can still be seen on the rock faces, along with the old paved path down which blocks were sledged and an abandoned column drum. The architect Manolis Korres has shown that this road runs downhill without a break all the way from the quarry to the Acropolis. Since the 18th century the cave has drawn travellers such as Richard Chandler and Edward Dodwell.

In the 10th to 12th centuries a small double church was built at the entrance of the cave inside the quarry: the southern chapel of St Spyridon is carved directly into the cave wall, while the northern chapel of St Nicholas was added later in masonry with a dome. Some of the 13th-century frescoes that decorated the two chapels were moved to the Byzantine and Christian Museum in Athens after they were damaged by military works in the late 1970s and early 1980s. The cave takes its modern name from a popular association with the 19th-century brigand Christos Davelis, though the link is thought to be legend rather than history.