Mahogany obsidian, like regular obsidian is formed through volcanic processes and is a naturally occurring glassy rock, which even shatters and breaks as such. The red/orange colouration is due to impurities of magnesium and iron during its formation, giving it red/orange streaks through out. It is some times also referred to as oak obsidian. In some cases, the colouration can be quite uniform, with almost the entire specimen appearing to be orange or red, such as the case with the obsidian we offer here. These rocks come from the USA and are available in 3 optional sizes, each piece will be supplied in a card tray with an information label.