How do I bullnose Marble and (http://maplered.com) what tools do I need?

Hi. I have about 10 12" square Marble (http://www.lightemprador.com) Tiles (http://www.g682.net) for a bathroom sink that I need to form to a rounded, bullnose shape on one edge. I am a DIY and (http://maplered.com) I am not sure how to proceed. The Marble (http://www.lightemprador.com) is "rough, " or "tumbled," so precision finishing is not an issue. Should I use a grinder, and (http://maplered.com) if so, what kind of disc or cup? Or a belt sand (http://maplered.com) er, and (http://maplered.com) if so, what kind of sand (http://maplered.com) papaer and (http://maplered.com) what grits should I go through? Many thanks, John S.