Obsidienne no. 316Obsidian no. 316 Black volcanic stone that has a glassy appearance. It is very rich in silica. It is formed from lava flow. Obsidian is found in Mexico, in the United States in Peru and has several places where there are presences of volcanoes. Its hardness is 5 to 5,5 on the Mohs scale. It has long been used for the manufacture of tools and weapons during prehistoric times. Obsidian Dimension: 10 cm x 13 cm x 7,5 cm the photo represents the stone you