Cartier Prisme Mystérieuse desk clock from the 1960s/70s featuring a rectangular fluted 18k yellow gold case with a concealed dial viewed through an optical prism system. It bears the poinçon EJ for Edmond Jaeger, and the case back screws down. The white dial displays painted Arabic numerals and a minute track, and blued steel sword hands indicate the time. Both the dial and case are signed Cartier. A manual-winding mechanical movement powers the clock, and the winding mechanism sits on the case back. The clock measures 2.8 × 1.7 × 1.7 cm and weighs 42.88 g gross. It comes with its original signed case, and it remains in excellent condition. The optical prism display relies on a patent filed in 1937 by Gaston Cusin, which creates an illusion whereby the dial appears or disappears depending on the viewing angle.
