Sotheby’s auctioned a patent of nobility issued to her husband, Dmitry Yegorovich Benardaki, in 1863 by Tsar Alexander II that mentions this portrait. The auction notes state that he worked himself up from the bottom as a Greek immigrant to Russia to become a wealthy industrialist. Her genealogical sketch is here.
From the museum’s Web site. I decreased the temperature to turn her dress from pale yellow to white and, hopefully, improve color fidelity.