Vintage Sand Cast Belt Buckle with Turquoise

Vintage Sand Cast Belt Buckle with Turquoise (Navajo).

Although the provenance of this piece is lost to history, and it has no markings (typical of sandcastings), there are some hints... A sticker on the back reads "1963 Arts and Crafts Show Winner".  And in ink "AUDD 36.00"  Very mysterious - we'd love to learn more in you have any thoughts!

3 3/4" wide X 2 5/8" tall. Meant for a 1 3/4" belt.