From Wikimedia.
This remake of the original Pourbus shows the ruff and jewelry with enhanced contrast.
Keywords: 1612, Pourbus - Frans the Younger, Margherita Gonzaga, Margherita Gonzaga di Lorena, Marguerite de Gonzague, Marguerite de Mantoue, duchesse de Lorraine, Gonzaga family, Lorraine family, Duchess, wavy coiffure, bangs, tiara, earrings, necklace, under-bodice, high vee neckline, jeweled lace-edged wide deep neckline ruff, tabbed over-bodice, vee neckline, lapels, carcanet necklace, tabbed hanging sleeves, jeweled sleeve ornament, false sleeves, ruffle cuffs, bracelets, basque waistline, farthingale, saya