An individual stone, either natural corundum, lab grown corundum, or cubic zirconia. Push them into the wet clay, and fire with the stone in place. Beautiful stones - they are top quality cut.
We carry out regular spot checks on our gems, especially when we get new stock or batches in. We test them in two different firings, 650ºC for 30minutes, and 800ºC for 45 minutes.
These gems show change after both firings, this particular gem changes colour. It turns to a slightly darker as the temperature gets higher. (This change is not guaranteed with every similar gem). We would recommend you to use this stone with a prong setting if you wanted the light green colour. Set the prong setting into the wet clay, and add the stone after firing.