Antique natural robins egg turquoise diamanté gold tone necklace

This is a mystery antique necklace. Made with high quality robins egg color natural turquoise on gold tone base metal. The turquoise gemstones measure 5.8 (L) x 3.9 (W) millimeters. Why would high quality turquoise be used in making custom jewelry, well that is the mystery. There are 14 diamanté on each earring. I have a matching pair of earrings for this necklace which I will post separately. The necklace measures 17 inches and has a one inch extender chain. There is a tiny bit of metal tarnish on the chain portion of the necklace, otherwise in great vintage condition.