All, Please read the Tucson Show Guide page 80 about Songea corundum.
This is a classic example of how treatment effects the value of a
stone. They quote that Songea sapphire which was marketed before
heat treatment sold for 200-300 USD per carat, sold after treatment
for double or more. They also disclosed that some of the sapphires
changed into bright red colors. Yes, into ruby by GIA standards.
This is the disclosure that the FTC Guidelines addressed with the
"value" statement. Not the comparison of a treated stone and a
natural of stone of the same grade. Colored Stone expected this
material to be widely available in Tucson. I wonder if this
treatment can be identified? Do you think this treatment will be
disclosed? How much of this material will show up in parcels of
melee? Also be advised that China is marketing synthetic quartz,
synthetic beryl, and synthetic corundum in large quantities to the
US.
Gerry Galarneau