English rare gold diamond and ruby set repeater Circa 1750

Fine and rare gold agate, diamond and ruby set quarter repeating verge
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An English  fine and rare gold agate, diamond and ruby set quarter repeating verge watch, circa 1750, gilt full plate verge movement signed John Grantham London, pierced and engraved balance cock.
White enamel dial, Roman numerals, pierced and engraved inner case, outer set with repoussé scrolls, moss agate plates on the case back and bezel, ruby and diamond-set motifs on the edges, diamond-set push button piece to the band, signed on the movement.
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Diameter: 43 mm
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Signed: John Grantham  London
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G.H. Baillie, Watchmakers and Clockmakers of the World, p. 130, John Grantham is mentioned,  Mid 18c. q.rep. agate watch Stern. coll. which corresponds to the present example.