Rainbow Sterling?

This is a set (earrings and a pendant) that is a bit of a mystery to me. All pieces are marked "Rainbow Sterling" but appear to be rhodium plated and are a bit magnetic. The workmanship is very very good though. I tried to find anything on line but couldn't come up with anything other than a contemporary Chinese maker with a similar name but the mark seems to be different. However, I hope it is not Chinese because I do not collect contemporary items made in China. Because the earrings are screw-back, I believe that the set is no later than from the 70's; but I could be wrong. Any ideas would be greatly appreciated.

Thanks for looking:)