Peony brooch Designed by Van Cleef & Arpels Paris, France, 1937 Gold, platinum, diamonds, Mystery Set rubies Van Cleef & Arpels Collection Photo: Patrick Gries/Van Cleef & Arpels The Cooper-Hewitt National Design Museum’s blockbuster exhibition, “Set in Style: The Jewelry of Van Cleef & Arpels” is coming to a close this weekend, and it is