London’s Harrods is presenting extravagant and artistic jewelry designs during a two-week event featuring jewels from the Biennale des Antiquaires, the renowned art and antiques fair held at the Paris Grand Palais in early September. The Harrods exhibition (September 29 through October 12) highlights jewelry from Piaget, Graff, Boucheron, and Chaumet, among other top brands. It presents an opportunity for a wide range of visitors to see the extravagant designs and rare diamonds and gemstones that were on displ…