That’s what I’ve been taught as well, that a melted boric acid coating is acting as a thermal insulator to help prevent thermal shock (meaning the inside of the stone cooling at a different rate than the outside can lead to thermal shock right?)
Poodlepup3 wants to anneal a silver bracelet in a kiln. Annealing temp for sterling silver is 1100 F. Assuming these are diamonds and not a stone that looks like a diamond. I think that’s a safe temp to heat the diamonds to without damaging them. Do folks agree with that? I’ve never annealed in a kiln. I’m assuming that you still need to coat with boric acid right?
Side note, I checked the forum search engine and there are lots of threads about frosting diamonds, but I didn’t see a temperature of when it happens.
https://orchid.ganoksin.com/search?q=frosting%20a%20diamond
Here’s an interesting thread that I saw about annealing silver that goes way back in time in the forum. Kind of fun to see, Alan Revere chiming in on the topic. One of my concerns about annealing in a kiln was heating too long and heat hardening the metal. This thread talks about that as well.
It’s been a while, but I have frosted small diamonds (never a large one) a couple of times doing jewelry store retipping repairs. The diamond has had to get to a bright red heat, which is hotter than 1100 F, if that helps.
Jeff