Between the stone and metal ages, the volcanic glass obsidian was a favored material for all manner of sharps, and an object of trade.

Ustica is noteworthy for being the flattest (and least interesting) Sicilian island, where all obsidian artifacts came from trade. Pantelleria was a major source, and suffered an economic collapse at the onset of the bronze age. Now, Sicilian islands source the best capers.

My favorite islands to visit are Pantelleria, Favignana, and the four outer Aeolian islands Stromboli, Panarea, Filicudi, and Alicudi. Dunno if the communal fisherman's table on Alicudi is still a thing, but I'd call it my favorite restaurant in the world.