You can tell the difference by looking at the bottom of your dishes.
If there are any rough, unglazed areas that are not shiny, smooth and white, it’s stoneware.
In 1998, Corning sold its consumer products division off to World Kitchen, who began making “Corning Ware” out of stoneware.(Then again, Crock Pots last pretty much forever.) I’ll leave you with a couple of my favorite Corning Ware ads too.Additionally, Corning Ware place to buy extra glass and rubber lids for your existing pieces.I use the rubber lids all the time for freezing food in my Corning Ware dishes. ) So, anyway, I do a lot of cooking and freezing in my Corning Ware — I like to make extra batches of whatever I’m making, freeze them, then reheat and serve right out of the same dish.Most of the newer stoneware pieces are also stamped with a warning NOT to put them on the stovetop, like this piece: You really have to be careful, as in many cases the new stoneware versions are being made with the same (or very similar) molds as the old Pyroceram pieces.
The stoneware WILL break on the stovetop, and it’s not designed for freezer use either.