Hallmark on necklace

I have several pieces of silver and turquoise jewelry I inherited. 3 rings, a belt, and a necklace. The pendant on the necklace has a mark of JM. The pendant is about a 1 inch oval turquoise surrounded by a silver engraved feather on one side, and curlicues on the other. Any help would be appreciated.

I have several pieces of silver and turquoise jewelry I inherited. 3 rings, a belt, and a necklace. The pendant on the necklace has a mark of JM. The pendant is about a 1 inch oval turquoise surrounded by a silver engraved feather on one side, and curlicues on the other. Any help would be appreciated.