We installed vessel sinks on granite counter tops. The bottom of the granite has a mesh glued on it that makes an uneven surface. It was very difficult to tighten the nut under the sinks to get the leak to stop. Finally put plumbers putty between the granite and the rubber gasket. It does not leak after this was done. Will the combinatiion of rubber and putty hold up and should we have scraped off the resined-on mesh to make it smoother around the opening?

How to Install a Vessel Sink for Your Bathroom | eHow.com Here's a link that may help. I would also remove the mesh and putty and caulk with Silicon Jel. Good luck, Tom

Did you use any plumbers putty under the drain flange. You should not be relying on cauliking or any kind of sealant under the counter top to prevent a leak.