Vintage stoneware - microwave safe?

My mother just shipped me a set of unmarked, dark brown Crate and Barrel stoneware from the early 70's that was our kitchen china growing up. I'm tempted to toss out what I'm currently using and replace it with this set. Before making such a rash move, I filled one of the coffee mugs with water and put it in the microwave for 30 seconds to make sure things didn't go boom. No explosions, but the cup came out hotter than I expected.

Safe? Unsafe? Hang onto a few ceramic plates/bowels for microwaving? Having just moved, I'm on a purge kick, so any rational input is greatly appreciated. Thanks!

I don't see why it wouldn't work. We have been using Pfaltzgraff stoneware ( circa 1980 ) in our microwaves since the beginning without any issues. The pieces do get hot but nothing has ever cracked or exploded.

I'm not so sure that would be "microwave safe." I could be wrong but I thought that one of the ways to tell if something is relatively safe is the heat test. If it comes out hot to the touch, then it's probably not safe for the microwave. I have a couple of bowls that are relatively new but don't have the microwave safe stamp on the bottom (Crate & Barrel) and they get hot in the microwave so I don't use them. My other plates that have the stamp don't get hot to the touch.

Again, look into this as I could be wrong but I would think that they are not safe for the microwave.

This has to do with the glazing used on the piece. Some glazes are not microwave safe due to metal used as part of the formulation. The heat test, as tyrus point out, is a good way to check, but be careful because the dish might be extremely hot to the touch if the glaze is not microwave safe. Put it in the microwave with a small amount of water in it and microwave for a short period of time (no more than 30 seconds) to do the test.

stevez wrote:This has to do with the glazing used on the piece. Some glazes are not microwave safe due to metal used as part of the formulation. The heat test, as tyrus point out, is a good way to check, but be careful because the dish might be extremely hot to the touch if the glaze is not microwave safe. Put it in the microwave with a small amount of water in it and microwave for a short period of time (no more than 30 seconds) to do the test.

That I did, and the dish came out hot, so I guess I have my answer. Funny thing is, when I was a kid, I remember my mother putting these plates in the oven. Progress isn't so wonderful in this case, I guess. Thanks all for the help, I'll go ahead and keep a couple of ceramic plates strictly for microwaving!