Sooz, that kind of crazing usually happens when there are heat stresses. The material (usually clay) and glaze (glass, really) expand and contract at different rates, and when the heating is uneven, especially in the microwave, the stresses can show like that. It usually is below the surface as you perceived. My bigger issue with over 40 years is that that was before they were really concerned with the metals used in the glazes. That color is less likely to have heavy metals than warmer and richer colors, but given everything, and that nice baking dishes aren't all that expensive, I'd retire it to being a catch all or scrap holder, and get a new dish.

Re the packaged meats, I call it "hermetically sealed chicken". I don't really approve of it so much, but it's so convenient, I give in an buy it sometimes. They suck all the air out, like they do with the washed lettuce, and perhaps they also wash the chicken, but it's mostly that it's hard for the bacteria to grow. The cold of the fridge retards actual decay.

Thanks, plllog, for the explanation about the baking dish!

As for the chicken, the package (and other packages of the same in the refrigerator section of Aldi) didn't have the air sucked out of it (like a food saver would suck out the air). This stuff really can be convenient and it's my first time trying it.

Neither does the lettuce. I don't know for sure about the chicken, but the lettuce has nitrogen. It's the oxygen, they're trying to get rid of. The chicken from Trader Joe's is what I've bought. It's decent quality chick, and usually does last until the date.

I disagree on the dish...I think because the crackling is only on the inside it's cosmetic. Done on purpose....called grackle glazed. Is there a back stamp on the bottom? I have a lovely antique pottery pie plate that has a crackely glaze.....and when I baked a pie in it....grease oozed out of the bottom of that pie plate....dark nasty grease. It seems the crackles were through the glaze and the pottery inside was saturated with grease from years of pie baking and oozed out! I now only use the dish for decorative plating and holding a pile of apples on the counter. it has had several rides in the dishwasher but I haven't baked another pie in it!

As for the chicken, the package is pumped full of nitrogen and CO2 to retard spoilage.
https://books.google.com/books?id=8gfrBwAAQBAJ&pg=PA21&lpg=PA21&dq=nitrogen+in+packaged+meats+to+retard+spoiling&source=bl&ots=K-h3jlBmaO&sig=ACfU3U20huJIGDafLJgkYL3FpIhc7zsh_Q&hl=en&sa=X&ved=2ahUKEwjJxJbXqszlAhVDSK0KHfQrBzAQ6AEwBXoECAgQAQ#v=onepage&q=nitrogen%20in%20packaged%20meats%20to%20retard%20spoiling&f=false

Linda, the dish, when I received it decades ago, was pristine white, no crackling/crazing. It was over time that the crackling occurred--seemingly all at once! Thanks for ringing in here!

Then likely it's got "goo" soaked into the pottery to give it that dark color. You can soak it for several days in a2 0% hydrogen peroxide solution and it will remove the dark....but I still wouldn't use it for anything but putting whole fruit in on the counter!

Gorgeous dish. I love the crazing. I would avoid using it in the microwave and be careful not to add heat stress to it (e.g. cold dish into hot oven; hot dish into cool water, and so on.

You can use it for salads (like Thai shrimp and cellophane noodles!), or make a tiramisu in it. Using it as a simple serving dish (garden ripe tomatoes, basil, mozzarella, olive oil & balsamic vinegar) would allow the lovely color and crazing pattern to be seen. Or you can just ship it to me.

it’s a lovely dish.