Vintage Navajo turquoise Ring in Size 11.  
Very unique turquoise stone with a black line down the center.  Ring looks to have been worn a lot, has a very nice aged patina. Has a very rich turquoise color.  Length of ring at widest part is about 1 inch.  Width at widest part of rope setting is about 3/4 inch.  
I find no maker’s mark on this vintage ring.  It’s a stunner!