Antique Back & Front 9ct Gold Locket. The above locket is stamped very clearly “Front 9ct Back”. These Antique Back & Front Gold lockets, mostly made in Birmingham, were created from the beginning of the 1900s through to the 1930s, the back and the front and the top bail for the chain being in 9ct Gold and some, or all of the rest being in base metal, purely for the sake of economy, in the attempt to use less Gold and  keep the price down.
In the case of the above locket the hinge is in Gold and the top ring, and of course the back and the front, and the interior framework for the images, including the flanges for keeping the images in place, are not in Gold.
Interestingly, the hand-engraving of the 9ct Gold front and back of this locket is first-rate, indicating that the decision to use them in a “Back & Front” was made in another part of the workshop at a later date, for the engraving is as good as it gets in Gold Victorian lockets.