Do you have cracks in the slab or sphere you are working on and afraid it might fall apart while you are working on it? Opticon might be the answer. Although the directions on the box are long and involved, we have found that placing your dry specimen under a heat lamp until it is hot and then applying the opticon mixture works best.
Mix 1 teaspoon of sealer to 8 -10 drops of hardner. Mix well.
With a popsicle stick, apply to heated rock that has been placed on a piece of waxed paper. Allow to dry overnight.
If working on a sphere, it helps to put it in a sandwich bag with the sealer mixture to coat it completely. Remove from bag to harden.
Wash your hands with soap and warm water when finished and wear disposable gloves if you have sensitive skin.