From top: Finn black diamond heart necklace, $1,425 at
finnjewelry.com; Tasaki Collection by Thakoon pearl necklace, $2,400 at Jeffrey New York; Jemma Wynne rosecut diamond necklace, $8,820 at ylang23.com; Andrea Fohrman Moon and Stars necklace, $3,750 at ylang23.com