From Wikimedia.
The ornament on the front of Margherita's skirt can seen in this photo of her wearing the same dress shown in this photo, this photo, and this one.
Keywords: Margherita di Savoia, Margherita of Savoia, Queen Margherita, Princess, Queen, Savoia family, Italian, long straight coiffure, floral headdress, off shoulder scoop neckline, modesty piece, bertha, cap sleeves, waist band, natural waistline, crinoline, jeweled neck band, bracelets