Antique Art Nouveau Platinum Diamonds Necklace there are 101 diamonds 2.90 Carats Diamonds TCW. The diamonds are mostly old European cuts averaging I color and SI-1 clarity. The necklace chain measures 14-3/8 inches long. The center diamond is .65 carat. The necklace is beautifully designed. The pendant portion measures 1-3/4 inches wide by 2-3/8 inches high. It is in excellent condition and weighs 9.7 grams.