Help with Belt Buckle

Hello all,
I would appreciate any information on the pictured belt buckle. I acquired it a couple of years ago while in Arizona from a Navajo family. It measures 3 1/2 x 2 1/2, my scale reads 2oz or 60 grams on the gram scale. It has a D for a hallmark. I believe the inlay is turquoise and coral? I have no idea of its value, history, artist etc… Prior owner stated it was owned by a grandmother. That’s all I know about it. Internet searches have not been productive. Any help would be greatly appreciated. It appears unused and hesitant to even wear it not knowing more about it. Thanks


<img src=/uploads/db1846/original/1X/6de37fbe5788186bb12419eb1431e9eb8ad3a05f.jpg">

<img src=/uploads/db1846/original/1X/0ba2e2c67c6bd492d409d507984b391406e72034.jpg">