A rock crystal 'Scintillante' miniature travel clock by Van Cleef & Arpels

A rock crystal 'Scintillante' miniature travel clock by Van Cleef & Arpels, c.1930's, the signed oval dial with baton and Arabic numerals, in faceted rock crystal case, manual movement visible through the rock crystal when viewed from above but concealed by a mirror illusion when viewed through the oval side sections, rose-cut diamond winder, signed at 6, 30 x 20 x 17mm, fitted case with magnetic arms which suspend and swivel the clock above a mirror