A tool I find essential for making glass jewelry (besides the glass grinder) is my Taurus Ring Saw. It uses a very strong and flexible diamond coated stainless steel ring which rotates around pulling cooling and lubricationg water from the reservoir beneath the bed of the saw.
It is available with a standard blade, a thin blade, a mega blade( for cutting stone/marble) a dichroic blade (fine grit so as not to chip dichroic coating), and a separating blade (for inside cuts).
The diamond coating on the blades (as with glass ginder bits) do not cut flesh and are very safe to use. They will only cut hard materials, so keep your fingernails and jewelry away from the blade. Diamond blades will also make short work of a callus.