i won an M3 blank at our pen turners picnic last summer. when i finally decided on the kit to use with it, i turned it. that was the hardest stuff i've ever laid tool to. i might not have had the sharpest tools, but i did resharpen every couple of minutes.
when i finally was done, even after all the polishing, it still went 'matte' on the finish.
while it was on the lathe i used MM up to 12000, then plastic polish, and even some Ren Wax.....it was shiney on the lathe....but the next day it was matte, now that i think of it....maybe some CA to seal it first....oh well. here's a pic of mine....it's M3 black and gold (mostly gold) on a blk Ti baron