An extremely rare ref. 15933 ‘Onyx’ Lemania 2310 ébauche chronograph, the only surviving onyx example known, thought to be one of three ever made. The 39mm case is unique to this reference, highly intricate with 3-piece construction, a bezel inlaid with polished onyx, hobnail exhibition caseback, and flared, stepped lugs. Its movement is finely finished with freehand engraving in floral motif, mirror anglage, and aggressive skeletonization, leaving various sections of the chronograph entirely transparent. Finally, it sports black feuille hands and and two thin decagonal registers. In period, this chronograph sold for 76000 CHF, created at special order request of a client. Now, it is testament to Piaget’s ample ability and love of watchmaking.