Zirconium

Zirconium 

Zirconium is great for wedding rings because it is durable and has a strong resistance to corrosion. 

Zirconium in its original form is naturally grey-white, but black zirconium is popular in the jewellery industry at the moment. The finish is achieved by putting zirconium through an oxidation process

No matter what the finish, black zirconium is very resistant to corrosion and scratching.