The real-estate mogul Steve Wynn once turned his Picasso painting into an upper-arm bracelet when he accidentally knocked his elbow through the canvas. The collector Diane Venet took a more straightforward approach to art as jewelry. Since 1967, Venet has collected adornments designed by the biggest names in the art world. Of her 230-piece collection—which includes a Jeff Koons platinum rabbit pendant, a Man Ray gold eye mask, and a Damien Hirst charm bracelet—180 are on display in Monaco. —J.D.