How do you use polymer clay with rhinestones crystals Swarovski hot fix and other sparkles

Yes, you can use rhinestones and crystals with polymer clay. The way you add them to your clay depends on what type, whether they have hot fix backings, and so on. Do not use acrylic or resin “rhinestones“ as these are not great to put in your oven. Most of them won’t exactly “melt“ however usually you just don’t know the quality or materials used to make them, so you wouldn’t want to expose them to heat or to let them put fumes out into your home. Yes, many semiprecious stones can also be put into your clay, just do your research and make sure they can withstand the relatively low heat used to cure the clay. For example, opals are notoriously fragile because they dry out- and the oven, although not really hot, will dry them out further (causing them to crack).