If you are looking for a ring that is scratch proof and forever keep its shine than our Tungsten Carbide rings are for you Tungsten Carbide is ranked second hardest next to diamond on the Mohs scale diamond being a 10 followed by Tungsten Carbide as 9. All of our Tungsten rings are Cobalt Free and hypoallergenic. Our rings will not cause skin irritations or turn your fingers green. Due to the Hardness of Tungsten these rings can be laser engraved but not hand engraved.