Fine and rare Swiss 18 carat yellow gold coin watch Circa 1980

Gold coin watch by Piaget
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A fine and extremely rare, Swiss, Piaget, Johnny Stark presente Mireille Mathieu coin watch case made by Huguenin, manual wind, 18k yellow gold coin watch, circa 1980. Manual winding nickel lever movement, 18 jewels, mono-metallic balance.
Champagne coloured dial, painted black baton indexes, blued steel hands—18-carat yellow gold case with a concealed 18k yellow gold Johnny Stark Mireille Mathieu coin watch. Case, dial, and movement signed.
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Diameter: 35 mm
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Signed: Piaget Swiss