Obsidian cores (Photo)

Obsidian, a volcanic glass, was the material of choice for chipped stone tools, especially blades, in prehistory. It occurs on Melos, Antiparos, and Giali at Nisyros, but Melian obsidian was the most widely
distributed. In the late Early Cycladic I and Early Cycladic II periods, obsidian cores, from which blades had been chipped, were often reused as pestles for preparing and mixing pigments in marble bowls, and these are occasionally found in tombs.

Photo from 'Cycladic Society 5000 years ago' exhibition Catalogue
© Museum of Cycladic Art