14k gold vintage turquoise solitaire ring size 5 buying

Product Name: 14k gold vintage turquoise solitaire ring size 5 buying
Vintage possibly antique solid 14k gold signed 14k AIS CO. oval Excellent color turquoise stone about 5-6 mm long. I'm not sure if it's real turquoise or not, but I think it is. The setting has a scroll like filigree design in The band buying below the setting. The stone is slightly loose in the setting. 3 of the prongs are tight, one looks like it needs to be tightened which is an easy fix. Weighs 1.75 grams. Size 5. Can be resized but your local jeweler. I tried finding information on who signs their jewelry ais co and I did not find the full name in my brief research but I've seen many other well made pieces with high quality stones with the same company mark.