The necklace graduates, which you would not tend to see with imitation pearls. The overtones of some of the pearls are a bit greener than others, and I see what look like blemishes on the 5th pearls from the clasp in the first photo of post #2, unless those are reflections. I'm leaning toward high quality, well-matched Tahitian pearls, but by all means do the "tooth test" Mtummybear!