Mokume-gane - Knife Handle Material
Mokume, actually called Mokume-Gane in it's full name, was created in the 17th century in Japan and initially used for sword fittings. Traditionally, gold, silver and copper were used in the production of Mokume-Gane, but now, modern methods of production allow us to use a much wider variety of metals. Modern Mokume is usually made form a combination of Gold, Silver, Copper, Bronze, and Brass, though it can include metals such as platinum and iron as well. However, in knives, gold is not used as often due to cost, so more affordable Mokume suitable for use in knives is usually made from copper, silver and brass.
It looks similar to Damascus with its layers of laminated metals, and is made by layering the metals onto each other and firing the stack of metal in a kiln in order to fuse the metals together. After that, the billet is hammered down in various ways to create the patterns that we see, which very much resemble damascus steel.
Mokume-Gane stands for "Wood Eye Metal" in Japanese. This name of course is because of the unique burl-like patterns found in Mokume. It is mostly used only in custom knifemaking for bolsters. Since Mokume almost always contains an oxidizing layer such as silver or copper, it slowly changes color with use as your hands make contact with it and as it is exposed to the air. Mokume-Gane is also used a lot in high-end jewelry, though it has yet to become a mainstream material.