This may be Franziska Xavera Ungnad von Weissenwolf (1773–1859) who married Alois Wenzel von Kaunitz-Rietberg in 1798.
From Wikimedia.
Franziska wears a jewel-trimmed version of a revolutionary dress for her 1805 Kauffman portrait.
Keywords: 1805, Kauffman, Franziska von Kaunitz-Rietberg, von Weissenwolf family, von Kaunitz-Rietberg family, Countess, German, turban, scoop neckline, long close sleeves, jeweled waist band, Empire waistline, close skirt, jeweled bodice ornament, bracelets, wrap