New vintage Barbie pink rose zircon October birthstone silver ring

New vintage Barbie pink rose zircon October birthstone silver ring Quick list I misplaced my ring sizer. Just based off my previously sized rings: It’s bigger than 7.5. Probably an 8. So many types of Birthstone jewellery were popular. For children and adults. This is adult sized. New vintage c. 1970s. Long hallmark that I can’t make out (see several pictures). Just found another ring with a clearer hallmark: STERLING ESP0 which means it’s sterling silver electroplated. Very solid simple smooth band. I polished it with a little toothpaste. Some pictures are from before it was polished. Not sure if it’s genuine or synthetic stone. Dark vivid pink purple. 8 sided top. Lots of facets. Deep set prongs in cathedral setting. Split shank.