Black Zirconium is Zirconium that is heat treated until it attains a very hard, durable black coating. The naturally silver colored metal is placed in a kiln at very high temperatures until the extreme heat causes oxidization. The oxidization layer is as hard as sapphire. 

The ring really is a very dark grey, which is one of the qualities that set it apart from Black Ceramic.  Also unlike the ceramic, the color of the Black Zirconium is- very hard- layer, so the ring will develop a patina over time.  

It is completely hypoallergenic.

Comfort fit.

Hardness Guide: