The shape of the rim on this rather large red-polished vessel is different on the two sides of the sherd, in one case rounded, in the other pointed. The surface treatments are an abraded red polish on both sides, though particularly abaded on the interior. It's possible that there's a handle or spout emerging from one of the extant sides of the rim because the rim plan isn't perfectly round. There also seems to be a black inclusion, perhaps obsidian or grit. Diameter may be wrong because I had to use an incorrect rim chart for a vessel of this size.
From Interior to Exterior