Santo Domingo Shell Lapis Lazuli Inlay Drop Earrings Native American Vintage S

Vintage Santo Domingo Shell and Lapis Lazuli Earrings Native American Inlaid. Good condition. Sold as shown in photos. Please view all photos. There is a black material on the back of earring and small amount on front as shown in pictures. Unsure if this is excess glue or what it may be. Earrings are sold as is. Earrings have not been cleaned. Any questions please let me know. Thanks for looking.