Does Diffusion implies Heated?

[Cave Keeper]

If a stone is described as having undergone diffusion, does that mean it has undergone heat treatment?

 

[Richard Sherwood]

Yes. The beryllium diffused sapphires have undergone heat treatment at 1780 to 1800 degrees from somewhere between 25 to 100 hours.

http://www.agta.org/consumer/gtclab/treatedsapps04.htm