Inlaid Butterfly Pin signed not stamped

I bought this at an estate sale today. It is not stamped but with markings. There are what appears to be initials with a symbol over them. Having learned from this site how important patina is for dating a piece, I cleaned as little as I could for a better view of the artist’s signature. I believe it is turquoise and onyx and silver. I saw so many beautiful butterfly pins by several Native American artists. The shapes were as varied as the butterflies in nature. Does anyone know who made it, how old it is and the mine the turquoise might be from? Would this be Zuni ? Navajo? I am impressed by how the turquoise was laid into the onyx. What do you think it is worth? I bought it for my grand daughter. She and I used to observe the butterflies in my flower garden she was little. Thank you all. Have a wonderful weekend.