Zirconium is also a elemental metal and it is very similar to titanium. It’s primary use is for coating fuel rods in nuclear reactors. The main difference between titanium and zirconium is the color of zirconium after a special heating process. During this heating process, the zirconium will turn black and have a extremely hard ceramic layer on the surface. This layer is as hard as sapphires and will not scratch under normal conditions like day to day wear.