8mm Cobalt & Carbon Fiber Mens Band8mm Cobalt & Carbon Fiber Mens Band Cobalt boasts a beautiful, Platinum like color which goes throughout the ring. Cobalt rings will not chip or crack, making it great for diamonds and custom work. Cobalt rings are malleable up to a half size; however, we recommend sending it to us for a free resize. Cobalt is a light weight and hypoallergenic. In case of an emergency, cobalt rings can be removed with a diamond tip ring cutter. Cobalt is often used in