Thank you all. I have two 7 band trinity rings, one platinum one tri-color. The hallmarks are different on both. One has the SNOE w/ the heart, (the gold) and a serial number, with the Cartier in script and 750--the other (platinum) has the Cartier in script with the c inside the circle, w/ the metal purity stamp and then the Cartier in block w/ the year. Both were authenticated but I read an article that Cartier can't even 100 percent verify serial numbers (especially on jewelry) and there isn't an archive with every maker mark that was in use.