I have one, with white bobbles on, I use mine in the ordinary oven, as far as I know they are made to withstand great heat, they are made of the same stuff, space shuttle nose cones are.
Now, it's supposed to be for browning stuff in the microwave. I was trying think how I might describe it, according to Mr P, it's ceramic with black bobbles on the bottom and a glass lid. (Even I had worked that bit out!)
Question is, would it be safe to use in an ordinary oven?
(I have never actually used it for anything, I sort of inherited it along with a cat and a lot of other kitchen stuff)