Mosaic on top of glass

You would have to use glass that is at least 1 inch thick. Mosaics are generally made up of stone pieces and cemented to the base with grout. This can make the table very heavy and if the glass is not thick and strong enough it can crack and break up. But the main point is that the table will be almost impossible to move because of its weight.

It definitely is possible to mosaic a glass substrate such as your glass tabletop but you definitely need to take into consideration the weight factor like Rosie said.  Mosaics can be very heavy so you need to make sure you have a strong and stable surface.  However, many mosaic artists specialize in mosaics on glass substrates and silicone adhesive makes a great glue for adhering mosaic tile to glass.  For more information on mosaics and for great mosaic supplies visit www.opusmosaics.com