In response to your PM, it would be very hard to put an exact date on this button. Is it hollow inside? Its looks 2 piece and looks like a modern type of self shank. The iron back makes it impossible to recover any backmark. May be heavy silver plated. The designs were used by many different button and clothing manufacturers. The best you could ask for is post 1900, 20th century civilian fashion blazer button.. Waterbury Button Co. still offers this fashion design today.
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