Backwards 6 over a Lowercase m? Or an open O?

[Psalmbody]

I honestly have no idea!
Picked this up at a thrift store but I've never seen this mark before. Google searches are fruitless.
This is the only mark on the bracelet. 925 with an m or sideways 3 in the denominator part of that fraction, and an open-ended o or maybe a backwards c or 6? I've searched for all of that and nothing came up.

Any help is appreciated!

[luvintage]

Hi there--don't know if you are still looking for info on the mark, I recently acquired a piece of jewelry with the same mark and eventually someone helped me with it. It's Danbury Mint. As soon as I was told this, I saw it made perfect sense.