Alum, the salt exuded from the earth “…quod intellegitur salsugo terrae”, and very useful for dyeing wool and cleaning gold, according to Pliny the Elder, 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, known to scholars as Richborough 527 amphorae, produced in Lipari where the factory was found, and, transported not only alum but also sulphur and capers.