A striking cabochon of 'Cosmic' Obsidian, a natural volcanic glass from Lipari, Italy.
The black transparent glass holds small white spherules of Cristobalite, a silicon dioxide mineral which only forms at high temperatures, which are scattered through the stones to produce an attractive 'cosmic' scene.
Under magnification, tiny pyrite flecks line the inner surfaces of the Cristobalite spheres (images 4 and 5).
weight: 15.24 carats
shape: Oval cabochon
dimensions: 35.73 x 14.97 x 4.05 mm