Hi just thought I would share some photo’s from the place in Chanthaburi Thailand where they treat and fill glass filled ruby.
they initially use acid on the ruby to clean out all the cracks etc and then put it in a crucible with powder mixture of glass to heat it in oven up to 1200 degrees for about 8 hours.
a second heat treatement is then done at a lesser temperature for about 3 hours
I also saw some experiment with yellow and green sapphire being trialled. They are and will continue to be on the market as well.
one picture is of the ruby ready to be glass filled in the kiln and the other is of the ruby that has come out of the kiln and is ready to be snipped apart then put into a tumbler to take any sharp edges off the pieces.