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This is a silver-mounted cork. These are usually made of electroplated metal, while others have the names engraved on mother-o'-pearl. Silver ones are unusual. They were made to stopper a serving bottle or carafe, and were usually for spirits.
This example is formed as a full crescent on a bell-shaped mount. It was made in Birmingham, (UK) in 1892 by H Matthews.
Dimensions: 3.75" long