At GIA.edu they were using their microscopes asGemaholic wrote: ↑Fri Jan 10, 2020 8:16 amUnfortunately the only way to know for sure is under a microscope or through chemical treatment.. I'd run a streak test on some of mine but it won't be accurate since streak tests are conducted in the rock's rough form (the powder created from rubbing the rock on the porcelain plate is how the streak color shows up and is determined).They can get in serious trouble for not disclosing they put a coating. It's one thing to heat treat tanzanite since that is accepted in the industry, but putting a coating on without telling customers is fraudulent. You can also try testing it in the sunlight to see if the pleochroism is present or looks faint. It's harder to do that test on pieces lower than AAA. I'll put some of mine under a microscope and let you know what I find. Stay tuned....JewelryQueen wrote: ↑Fri Jan 10, 2020 1:56 amCan't remember where I heard about the new grading. Was at least 2 months ago but I know it wasn't at SLC. And yes I have heard that there is some type of cobalt treatment being used on Tanzanite but do not know any specifics about it. I'll bet some of the more educated ladies can give you the scoop. I love this forum!
well and that is how they found it. I’m curious
to see what you find.