After extensive experimentation/hair-pulling/botched results, please consider sparing yourself the headache of stones and opting for steel. Regardless of your heat source: electric, propane, wood - steel is the way to go for consistent amazing results. Are there applications that use stone to great effect? Yes. But those are engineered that way. Most people don't have systems that benefit from that kind of engineering. If you want to work with your oven/grill/outdoor pizza cooker just get a steel and be done with it. PRO TIP: the thicker the better if you're going to be doing multiple pizzas as it carries the heat even better.