Navajo Belt buckle? Not a normal Hallmark

[MrsCK]

I was cleaning out a drawer and came across this belt buckle given to me years ago. I have tried all day to find the Hallmark that seems to be symbols instead of the normal "letter" hallmarks by native americans. Any help would be great. I have played with the lighting to get the best pictures I can of the hallmark and front side of buckle. The turquoise looks to have a piece of silver in it, is this normal?











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