Is 921 a Sterling Mark?

[pairofbaubles]

Hello everyone! I have a pair of art deco looking marcasite earrings (pierced) that are marked on the back of shiny silver metal, 921. I thought at first I was mistaken so I took out the loupe. It is marked 921 even though the 1 is slightly worn, it is still legible. Here are the earrings.

Front


And here is the closeup of the mark


Thanks for your help!
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[admin]

Hi,
I think it is just a poorly struck 925 mark. When stamping a piece, it is very difficult to hold the stamp perfectly straight, if off just a bit, one side or another will bite in deeply and the other faintly. Here's an exaggerated example from a French costume piece.


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