Sorry, pathetic question here, but I can't find an answer on t'internet. I have two casserole dishes, one is ceramic-looking with a pyrex glass lid, and the other is an M&S casserole dish that feels damned heavy, but I don't know if I can put either of them on the gas hob. Short of trying (and crying if they crack!), is there any way of telling whether or not they are hobbable? :o