Obsidian, the unique natural glass

Obsidian is a natural glass of volcanic origin derived from the cooling of an almost completely gas-less magma, similar to that of human production.
Much sought after in antiquity for the manufacture of sharp tools, mainly knives, it was one of the goods that animated trade in the Mediterranean and supported the economy of its places of extraction, such as Sardinia, the Aeolian Islands and Pantelleria, in prehistoric times. Today it is still used in small decorative objects, jewellery and scalpel blades.