Melos, Cyclades, is one of the most extensively mined islands in the Aegean and a leading exporter of bentonite and other industrial minerals. Melos is a volcanic island but lava producing volcanic activity is long extinct. Nevertheless, geothermal phenomena such as phreatic explosions, hot springs and solfataras continue to be present. Of the many types of light coloured rock, it is the white rock, altered by geothermic activity, that is significant here. Melian Earth was white and was famed in antiquity as the best white pigment.
Records regarding the value of white Melian Earth exist from the 4th c BC. Theophrastus (4th BC) described the earth as white, rough, and with a loose texture; Dioscorides (1st c AD) begged to differ, describing the earth as ash-coloured and good for extending painters' colours. Agricola, in the 16th century, was rather dismissive of the earth, labelling it of moderate importance to painters. Melian Earth's reputation as a quality white pigment was owed to the combined presence of kaolin, silica and alunite found amongst other places in Loulos, SE Melos and which gave the pigment opacity and good spreading power. Another important raw material was sulphur which was extracted both from deep veins as well as the fine effluorescences seen in the opening of vents (see image on the right). Sulphur extraction was very intensive in both the Roman period and the 19th c.
Images: view towards Kimolos from Phylakopi, N Melos: pumice tunnels at Sarakiniko, N Melos; solfataric crystals of sulphur, Kalamos, SE Melos.(images Effie Photos-Jones)