BOU-OBSOC-01 Origin: Mexico Grade: AA Dimensions: 30-40mm Weight: Approximately 50g Origin: Mexico Grade: AA = very high Very beautiful celestial eye obsidian sphere of 30-40mm Delivered with a wooden or plastic stand Colors and patterns may vary from one stone to another Note that the spheres were photographed using an artificial light source to best highlight their reflections. Obsidian is a volcanic rock rich in silica. Different types of obsidian exist. They differ due to the chemical composition of the rock. Obsidian is actually a natural glass. It forms during a silica-rich lava eruption with less than 3% water.