The Autronius combines comfort fit, brush finish and highly polished stepped rails for a great look. Cobalt Chrome Metal Values: Cobalt Chrome is a very popular, new fine metal for wedding rings. Cobalt looks like shiny platinum, yet has extreme hardness. Your Cobalt Chrome metal will serve you well. It will stay beautiful & won't tarnish. Cobalt Chrome is also a hypo-allergenic metal making it a great alternative metal option for your fine jewelry wedding ring.