I would like information on heat treating of Australian sapphires. There is a lot of info on the web , but specifics are hard to find, I need temp. required & for what time period to remove silk from sapphires, any help would be appreciated, Brian Harder
Check out this guy from Gem Mountain. At around the 10:30 point in the video, he talks about silk.
Bit of an art form heat treating. Temp is around 1750-1800C but then you have to consider the atmosphere, oxidising or reducing, soak time, speed of cooling etc. I find it better to pay the money and leave it to the experts who are doing it all the time. I use a guy in Rubyvale in the Qld gemfields.