Watch List notes:

USA, a coin locket, silver Trade Dollar, 1876, skillfully hollowed, the reverse 'invisibly' hinged, to reveal photograph of a young lady, host coin very fine, a well-made item of jewellery
These coin lockets turn up in commerce from time to time, nearly always using a Trade Dollar, but manufacturing jeweller remains stubbornly unknown.

Estimate: 200 - 250 GBP