Despotiko is dominated by metamorphic rocks with foliation surfaces dipping quite uniformly towards the southwest at shallow angles. The structurally lowest parts in the north and northeast of the island consist of grey, strongly foliated, mylonitic ortho-gneiss with abundant cross-cutting pegmatite dikes that become more and more deformed and rotated parallel to the foliation towards the hanging wall. The ortho-gneiss is followed by up to several metres thick, prominent white, strongly foliated, mylonitic gneiss. Higher up are medium-grained, white calcite marble, followed by greenish-white gneiss and an alternation of chlorite epidote schist and thin marble layers, on top of which are found chlorite epidote gneiss and retrogressed amphibolite as well as some small serpentinite lenses. The structurally highest parts in the south and southwest of the island comprise thick white to yellowish, fine grained dolomite marble with thin layers of dark grey, carbonaceous calcite marble.