Why? Diamond has very low thermal expansion, so no risk of stress/embrittlement/cracks from uneven heating.

Or you mean it'll catch fire? Also not a concern. That is supposed to happen at a temperature well above anything useful for cooking.

The temperature of the blue flame on a stove should be above 1000 Celsius, well above what’s required to oxidise diamonds. They won’t catch fire, but your diamond pan will erode. Once you remove it from the flame, it won’t continue “burning”.

Should be safe on electrical stoves though.

Would that >1000°C reach the surface though?

There are some heady boundary-layer effects and temperature/temp-conductivity gradient physics involved here. For simplicity sake, consider a plastic [1] bag full to the brim with water, held over open flame. Will bag melt (oxidize, erode)?

[1] polyethylene melts around 120-ish °C and ignites around 220-350 °C (sources vary)

Someone sells a diamond coated pan https://bluediamondshopping.com/

It's probably fine on the inside?

Why are you using a question mark.

The material would be 'fine', but I'm not sure how safe or effective it would be as I'm not a materials expert. Just considering the risk of the material. (Yeah, the material would be fine, is it safe and beneficial? That part of 'fine' I can't define.)

That's a good point. Have you done the experiment?

I think because it will burn your hand?

It’s safe to assume the handle is made from something else.

Just put them on inside only

But wasn't the point that diamond is a great hear conductor?

It would still work, if the bottom cladding were very thin, and a decent conductor.