The geological history of Lesvos is inextricably linked with the volcanic activity that took place 21.5 to 16.5 million years ago and led to the creation of large volcanoes, such as those in Lepetymnos, Vatoussa, Agra, Mesotopos and Anemotia. Volcanic eruptions shook the area of modern Lesvos. But the volcanoes were not only cause for destruction, since their activity led to the creation of important geosites and rocks.
The impressive lava domes in Molyvos and Ordymnos and the volcanic neck of Petra have been used by man as locations for the construction, respectively, of the Castle of Mythimna, the Ypsilos Monastery and the Church of Panagia Glykofiloussa, thanks to the resistance of their volcanic materials to weathering.
Many minerals and rocks, such as quartz and opal, ignimbrite and andesite, alum, bentonite, lead, zinc, magnesite, constitute valuable natural resources exploited by man over the years. The “alum earth” is a sulphate called alunite, associated with the volcanic activity on Lesvos. It was extracted in ancient times for medical purposes. One of the first natural materials used by man was flint, as evidenced by the archaeological excavations in the area Rodafnidia, near Lisvori. But, one of the first stone tools built and used to grind grains and process the fruit of the olive tree were the millstones made of volcanic rocks, which have played a leading role in the productive economy of the island.
Particular is also the raw material for the creation of the Lesvos ceramics, which have the unique ability to keep water cool. The raw material for their creation is pulverized ignimbrite, a volcanic rock associated with the activity of the large Lepetymnos volcano about 17 million years ago. The ceramics are created with a technique that has remained almost unchanged since the ancient times in the area of Agios Stefanos, in Mandamados.