Stephanie, I think there's a bit for trimming ceramic tile - that's probably what you need

There's so many bits to the Dremmel that it's kept me away from buying one. I think you need the diamond bit like on the wet saw and ring saw.

The bit you need is def diamond,I just know here in Canada, we pay at least $30 for the diamond bits, and I couldn't find a blade one, they just discontinued it?! But I do have a diamond drill bit. Do you have a couple of practice mugs, and a hand nipper and try that?