Signed vintage locket & chain in sterling w. original box

Very sweet 20mm diameter locket with etched leaf design on the front. Marked Sterling Silver and JAM on the back. JAM was a mark for J.A. Main jewellers of Birmingham, England. Another mark was Mainline which is written on the satin inside the original blue box. Comes with a fine 17" chain stamped on the clasp: Sterling (with a triangle symbol) and Germany. All in great condition. Missing one of the clear plastic inserts that are sometimes in lockets to protect the photo.