From thepeerage.com.
Anthonis van Dyck portrays Lady Katherine wearing a typically décolleté dress with what appears to be braided strands of pearls for a bodice ornament.
Keywords: 1640, van Dyck, Katherine Howard-d'Aubigny, Stuart family, Howard family, , Duchess, British, long hurluberlu coiffure, square décolletage, modesty piece, bows, puffed sleeves, necklace, earrings, jeweled bodice ornament, wrap