Check out Mokume rings. It is a Japanese style of forging:
Carbide: http://www.amazon.com/Gold-Plated-Mokume-Style-Tungsten-Carbide/dp/B002N6MFAC
Titanium: http://titaniumringco.com/rose-gold-and-shakudo-twist-mokume-175.html
I think Gizmodo had an article about it at one point.