my earrings

by Lynn
(Tucson, AZ USA)

I have a pair of large, "old miners diamond" cut. They appear to be alexanderite, about 1.5 ct each. The screw mount is about 3/4" long. On the side of each backing, there is a star with sickle on one side, and what appears to be a period, then the number 4, then what looks like an anchor. What do we have?