Are all statues made of marble?

Marble is not a color, but rather a type of rock. The color of the sculptures are due to the natural colors, shades, and patterns in the rock.

The reality is that the Greek marble works were brightly painted in reds, blues etc - the Greeks lived in a riot of colour, but this has disappeared over the centuries since. Some show traces of their former glory, but are hard to detect. This was first discovered in a 1920s excavation in a ravine at the back of the Acropolis in Athens which uncovered the statues of the gods broken up by the Persians in 480 BCE. After the Persians were driven off, the Athenians wondered what to do with the broken gods, and put them in the ravine waiting for the gods to tell them what to do. They became covered over and waited there for nearly two and a half thousand years, and revealed the real nature of Greek art, which was not the bland marble we imagined it to be.