I've seen some great faceted bead out of polymer clay, but but all of them are solid color. Here is a tutorial, in both single-page and video format, that shows how to make a geo bead in an ombre or marbled pattern. Be sure to check out all of my single-page tutorials where you will find a page on how to blend clay.
Since it's the new year, I've been trying to go through old canes and use up mixed clay. I found this process so mesmerizing! I never get tired of slicing into a ball of swirled clay. I love slicing the clay into cubes or geometric shapes, because the corners are so sharp and the sides are so clean. You can poke a hole with a needle before it's baked, or drill a hole afterward.