Theresa, I have noted a lot of differences in stones in the last
two years. My experience is that stones that have been
irridated and heated are much more brittle. Facet edges chip
easily and it is difficult to get a scratch free polish.
Morganite beryls have been especially finicky. Some quartz
materials can cause problems. The new lemon quartz and green
quartz are in this category. Sapphires have not been a problem.
No one that I know of has ever done a study to find out if
heating and radiation effect the durability of the stones. Some
stones are put through the process several times to furthur
enhance them. Does it effect the characteristics of the stone?
I do not know for sure.