New vintage blue zircon December aquamarine March birthstone silver ring

New vintage blue zircon December or aquamarine March birthstone silver ring So many types of Birthstone jewellery were popular. For children and adults. This is adult sized. New vintage c. 1970s. Hallmark: STERLING ESP0 which means it’s sterling silver electroplated. Very solid simple smooth band. I didn’t polish this but I can if someone asks and/or if I have time. Probably synthetic stone. Pretty light teal blue. 8 sided top. Lots of facets. Deep set prongs in cathedral setting. Split shank. Size 4.5 8 mm octagon / Diamond shape 8 mm tall from shank base to top of gem, 5 mm tall gallery Stepped beveled edges ~emerald cut