Princess Amalia von Preussen (1723-1787) as an Amazon by Antoine Pesne (location unknown to gogm)
Princess Amalia's silver ensemble may be the result of her being Abbess of Quedlinburg from 1755 on, a job that made her rich according to Wikipedia. Her Wikipedia article is here.
Princess Amalia wears a jacket and a vest, all of similar or matching silver brocade-type fabric and a tricorne hat in this portrait. The dress appears to be expanded by hoops (named panniers after the French word for basket) distended to the sides. Ribeiro noted in Dress in Eighteenth Century Europe, p. 43 (2002) that hoops reached a circumference of eleven feet and that by 1720, the front and back were flattened by a system of cords inside. Her dress has a masculine flavor with a tricorne hat, pocketed vest, overcoat (albeit long and flared to fit over her hooped skirt), and cravat. Ribeiro also wrote in Dress in Eighteenth Century Europe, p. 150 (2002) that "Many German princesses rode astride and dressed like men..."