French watch set with amethysts and shell-form decoration Circa 1830

Gold verge watch set with varicoloured gold decoration 
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A French gold verge watch set with amethysts and applied varicoloured gold shell-form decoration, circa 1830. The movement features an unsigned gilded full plate with a verge escapement, a plain flat three-arm balance, a decoratively pierced and engraved balance bridge, fusee and chain, and cylindrical pillars. The gold dial has an engine-turned design, a small satin-finished chapter ring with Roman numerals, a blued steel hour hand, and an outer minute ring with an aperture for winding. The gold case is applied throughout with vari-colour gold shell-form decoration, with the bezel and case back further enhanced with applied amethysts. The bezel and bow are similarly decorated, and the inside back bears French control marks for 1819–1838, with the pendant also marked for 1822–1838. The case back is numbered 18698 (possibly inverted 86981).
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Diameter: 45 mm
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Signed: No name
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The movement is functional and in good, clean condition. The dial is in good condition but is missing the minute hand. The case is also in good condition, with some tarnishing present.