18K gold, rock crystal and onyx, diamond-set, eight-day going Mystery clock, Cartier, Paris, circa 1925.

18K gold, rock crystal and onyx, diamond-set, eight-day going Mystery clock, Cartier, Paris, circa 1925. Cartier, Paris, circa 1925. Pendule Mysterieuse, Modele A. Very fine and rare 18K gold, rock crystal and onyx, diamond-set, eight-day going Mystery clock in original fitted leather travelling box and accompanied by the original key. C. Rectangular rock crystal case with moulded tapered pediment, yellow gold mounted on a rectangular onyx base. D. Mother-of-pearl chapter ring and frame with applied gold Roman numerals and further decoration, inner diamond-set border. Rose-cut diamond set hands. M. Rectangular brass frosted and gilt with going barrel, gilt platform with straight line lever escapement, cut bimetallic balance, Breguet balance spring. Signed on the base. Dim. 139 x 91 mm.