Mokume-Gane is a mixed metal laminate with distinctive layered pattern, in which sheets of metal were stacked and heated to form strips that could be forged and carved to increase the pattern's complexity. Developed in Japan in the 17th century. it was mostly used for sword fittings until a decline in the katana industry forced artisans proficient in this art into making purely decorative items.
The mokume-gane technique can be used with polymer clay. The technique consists of different colored sheets of clay that are stacked, then textured using a variety of tool and cutters. The resulting block of clay is then thinly sliced to reveal the interesting pattern created. These thinly sliced pieces can then be used as a veneer on any polymer clay piece that you choose.
Another method is to roll out sheets of different colors of polymer clay on the thickest setting of your pasta machine. Then applying different materials, such as, gold or silver leaf, acrylic paints, mica powders, or alcohol based inks. You let these applications dry, then press them together firmly and top the entire stack with an unpainted sheet or polymer clay. Then you texture and slice the block, using the same method as mentioned above.
I've never had much luck at this technique. I think I need a new and sharper clay blade to make it work but the following artists from the Polymer Clay Smooshers Guild on Art Fire have mastered this intricate technique.
Greystone Pink Layered Polymer Clay Pendant Necklace by Art Asylum
Polymer Clay Mokume-Gane Pendant by Sharp Art By Dawna
Stars and Asteroids Art Bracelet by Drunkenmimes