What do pearls symbolize in the novel, The Testaments: The Sequel to The Handmaid’s Tale?

Pearls symbolize the aims of the Pearl Girls missionaries to convert and collect girls and women from around the world into the Gileadean system of values. With their rarity, beauty, and their white appearance, they signify the traits that embody the vision of womanhood that Gilead seeks to instill: beautiful, virginal, but ultimately mere objects.