Another friggin polishing/grinding question

So I'm still working on that damn sink that I've hollowed out of a quartzite boulder. Problem now is, after sawing and (http://maplered.com) grinding out the basin, there's still lots of tool marks inside the basin (namely, deep striations and (http://maplered.com) some gauges left behind from the diamond cup wheel grinding). Today I destroyed a 50 grit polishing pad (wet) trying to grind out these tool marks. I got most of them out, but man it took me over an hour and (http://maplered.com) there's still quite a few left. There's got to be a better and (http://maplered.com) quicker way to buff out toolmarks before going to the polishing pads (I hope). Anyone?


Also, I noticed faint striations left behind by the 50 pad in some places...do these need to come out before I move on to 100 grit, or will each successive pad take care of it's predecessor's marks?

Thanks!