The island has an area of 73 sq.km. It is located between Kythnos and Sifnos. The subterrain is rich in iron ores, which constituted an object of mining and processing both in ancient and recent years (1880-1912). Among the rare minerals of the subterrain is the green quartz, the lievrite, the edemvergite, the barite, the garnet. The terrain is rocky, among the most infertile in the Cyclades, and semi-mountainous with the highest peak being that of Troulos (585m). The coasts form enclosed and windless coves, mainly on the south coast, and small sandy beaches (Koutalas, Livadi, Psili Ammos).