A diamond shape bordered on each side by a pyramid.

[paul wilson]

I have a hammered silver coctail shaker marked with a diamond bordered on each side by a pyramid and the number 504. I've tried to find out, but I'm lost. It's possibly art deco, and any help is appreciated.

[2209patrick]

The mark you describe sounds similar to a mark used by the Friedman Silver Company located in Brooklyn, New York. Founded in 1908 and bought by the Gorham Corporation in 1960. They used this mark on their silver plated and pewter pieces.
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[paul wilson]

Thanks so much for the help with my query! Paul