4x harder than Platinum, 5x harder than Gold and 7x harder than Silver: Cobalt is the ultimate contemporary metal. Benchmark’s naturally inert Cobalt contains a special blend of Cobalt and other alloys that exude extremely high luster and reliable strength. Because it is also hypoallergenic, scratch resistant and biocompatible, it has been used heavily in medical applications. Cobalt, unlike Tungsten, is shatter proof.