Genuine Solitaire Peridot Necklace Genuine peridot solitaire necklace. There is one genuine peridot set in four prongs that measures about 5mm in size. This pendant hangs on an adjustable 16-18" inch link chain. Peridot is the birthstone of August and a great gift to give for birthdays... MSRP: Was: Now: $185.50 - $927.50