Here is a $30,000 57.15Ct Peridot and Diamond Necklace in 14k white gold. This is part of a Jewelry Store stock that will be auctioned this week. "Cleopatra's favorite gem was Emeralds- however historians now believe that her Emeralds were actually Peridots. Peridots are one of the earliest mined gemstones with ancient written records dating back to 1500 Before Christ". Answers.com. This substantial Necklace will look great on your Queen. The lush Green Peridots accented with Diamonds will light up her neckline. It has an impressive Peridot and Diamond weight of 57.15Cts. This will make an unforgettable gift for her this year. It measures approximately 17" long. This 57.15Ct Peridot and Diamond Necklace in 14k white gold has a retail replacement cost of $30,000 and it will be auctioned with a surprisingly low reserve.