Sapphire Heat Treatment?

I’ve been given a number of rough Montana sapphires and would like to
heat treat them to bring out the color. Does anyone know the details
of the process?

I suspect that the max temperature may be 1000-1200C, but I do have
access to a computer-controlled oven that can provide slow ramp-up
and ramp-down times that are probably required.

Thanks

  • Brad Smith