With most baking stones, you get what's available — a uniform size and thickness. Maybe there's a choice of round or rectangular, or a couple of standard sizes, but you're still limited by what's available. The greatest benefit of the Fibrament baking stone is that you can specify exactly the size you want. There are several standard sizes, but if want something different you can order whatever you like; perfect for an odd-sized or custom oven. The stone I have is 15x17 and 3/4 inches thick. Greenish in color, the stone is simultaneously slick to the touch and bumpy. It's obviously not the same material as your usual stone.
The instruction that came with the stone explained that it needed to be cured, by heating at progressively higher temperatures. This is supposed to drive out any residual moisture, thereby preventing cracking. There are also warnings about NOT washing it with water. The recommend cleaning method is to brush it with a dry cloth, or if things are burned on, heat it until the stuff burns off, and then brush off the residue.
Like all the other pizzas, I preheated the oven for 1 hour at 550 degrees. At 45 minutes, the stone was 535 degrees and at one hour, it was 539 degrees. Because I ordered a slightly larger stone it made pizza placement easier than when I worked with some of the smaller stones. After the usual eight minutes, the pizza was baked and ready to go.
The bottom came out crispy and was nicely browned with darker patches. Of all the cooking surfaces tested so far, this one didn't produce the crispest bottom, but the results wouldn't disappoint.
The standard sizes of Fibrament stones range from $43-$90.