This White CZ (Cubic Zirconia) pack contains 25 Oval stones ranging from 5 to 7mm. These stones are safe to use in your PMC designs. Individual packs may vary. Please note, there is a +/- 0.2mm tolerance with these stones. Sizes may vary. Please note, even though these stones are marked as safe to use with metal clay, it is only a guideline under which they have been tested and stand a greater chance of survival. Any time these stones are fired there is a chance that their appearance could be altered or they could become damaged. Do not put these stones in a kiln for longer than 2 hours or at a higher temperature than 1650°F to 899°C.