The most marked Bismuth specimens are manmade and exhibit a very interesting hopper like shape. They form incredible geometric patterns in a stair step arrangement, resembling a stadium. This unusual shape is due to the crystal edges growing at different rates than the crystal faces. Bismuth is produced in a laboratory at 271°C from electronic grade highly refined bismuth. The several iridescent metallic colours which make Bismuth so unique is caused by light scattering at a very thin layer of bismuth oxide. Red, yellow, blue, green and purple are most commonly produced. Two-thirds of manufactured Bismuth is used for the production of drugs, pharmaceuticals and other chemicals.