Alum and sulphur, Vulcano’s most famous natural art forms

Alum, the salt sweated from the earth and very useful for dyeing wool and cleaning gold, has been a source of wealth for the Aeolian Islands since ancient times.
Alum mining had already been practised by the Romans who, in amphorae produced in Lipari where the factory was found, transported not only alum but also sulphur and capers.