This is a wonderful condition sterling silver and Navajo Sarah Dickens Ammonite ring size 7.  The colors of the Ammonite is blue and green and I believe its from Canada.  The top has a rare half design.  The top measures 38 mm by 12 mm and the quality craftsmanship shows.  It weighs 6 grams.  Please let me know if I can help you in any way.  Thanks for bidding