I've got a vase that I purchased years ago... hand thrown, sort of 'urn' style. I'm not sure how the coloration on it was done, but what the craftsman told me is that it's a 'burn-away' method, where they wrap or nest it in straw or something like that, and as it's firing, the material burns away to leave colored stains on the pottery. It looks great - unfortunately, it's not glazed on the inside! I discovered that it doesn't hold water, after putting some clippings in it and filling it up. Water everywhere... I don't bother with dry arrangements, so now it's just a pretty vase on top of the gun cabinet. Heh. The clay that was used was sort of a rusty beige color, and it's mottled with darker streaks and swaths, some sort of purplish, some more brown. Not sure if that's something you would want to look into or not, but it would make for a pretty neat snake hide, without including any glazing on the outside.