Her Wikipedia article is here.

Marguerite, Countess of Blessington by John Cochran after Le Commte (National Library of Ireland - Dublin Ireland)

Marguerite or Margaret Gardiner, Countess of Blessingon, née Powers, 2nd wife of Charles Gardiner, 1st Earl of Blessington engraved by W. Giller painted by E.T. Parris (National Library of Ireland - Dublin Ireland)

1839 Marguerite, Countess of Blessington by Hippolyte Masson (Newstead Abbey - Nottingham, East Midlands UK)
