When sizing rings with heat sensitive stones in silver I always place the stone under water. However, the water draws heat off the ring (as if silver was not bad enough on it's own). To help the situation, I place a small piece of firebrick through the finger hole of the ring. I use a piece 12 mm X 5 mm X 30 mm. This helps protect the stones but more importantly it reflects the heat back up to the bottom of the shank. This makes sizings MUCH easier.
- Unknown Jeweler