I used to buy pizza stones regularly. All too regularly, in fact, as they inevitably seemed to shatter somewhere around the fifth or sixth use. So I switched to terra cotta floor tiles from Home Depot. They shattered, but they were cheap and easy to replace. But I figure nothing, no how, no way, is going to damage my newest pizza "stone." It's a 15-pound, almost 1/2-inch-thick sheet of solid steel called, appropriately enough, Baking Steel.
Andris Lagsdin is the inventor. He also happened to be a former pizza cook who worked for his family's Massachusetts-based steel company. Talk about kismet. He was frustrated by the fragility of ceramics (see, I told you) and was inspired by a line in Nathan Myhrvold's "Molecular Cuisine" that talked about the superior thermal conductivity of steel.
In August, he popped his idea for the Baking Steel up on Kickstarter and quickly generated more than $38,000 in pledges to start manufacturing. He started shipping in September and has already been featured in Bon Appetit magazine and on the Serious Eats blog.
You use a Baking Steel much as you would a ceramic stone – put it on the lowest rack and heat at the highest oven temperature for at least 45 minutes. Slide the dough straight onto the metal and it'll be cooked in a flash (seriously, some of the testimonials claim baking times of less than 4 minutes).