I've got a 3 ⅛" x 2" x 1 ⅛" that's pretty pure. I haven't put a razor to it, but it stays on my coffee table with my knife tune up gear though.Looks almost as pure as the little 3x1" one I had (have? I'd have to check)... that was a passable razor finisher.
edit: Checked and surprisingly, yes I still have it.