Found travertine slab for pizza stone -- your thoughts, please
A friend of mine knew I wanted a pizza stone, and he picked up a 1" thick slab of travertine for me at Urban Ore (http://urbanore.com/) that fits nicely in my oven.
Functionally it would work great for pizza, but I don't know where this travertine has been or what it's come in contact with. Is it useable? Usable after a special cleaning? Useable with a silicone mat or other protective layer on top? Should I use it as a flagstone instead?
Travertine is limestone, which is soft (for a stone) and porous. Because of the latter property, it is treated with sealants when it is to be used as a building material. Even if the stone were not damaged, you might not want any possible fumes from sealants in your oven. That's just my hunch, not an expert opinion.
They also often use filler to make it smooth. So if it is smooth, they probably used epoxy to fill the holes which I would not want to cook on. My pizza stone only cost $10.
If the travertine is NOT "filled and honed" then it's probably fine. Just make sure that it is merely a slab of natural travertine, and has not been sealed. It is VERY easy to test if it has been sealed - just ask them to sprinkle some water on top of it. If it beads up then it's been sealed. Otherwise, not, and the wet areas will then immediately look darker with more ehanced colors. A sealed surface may not "look" any different so it's not safe to just trust how the light hits it. The water test is essential.
We redid our master bath this year with all natural stone, so I learned more than I ever cared to about this stuff.