This is probably the dress seen in this image and this image.
Keywords: 1870, Malenkaya-Glosoli, Maria Feodorovna (1847-1928), Prinsesse Dagmar, Princess Dagmar, Dagmar (kejserinde af Rusland), Marie Sophie Frederikke Dagmar, Мария Фёдоровна (жена Александра III), Glucksberg family, Romanov family, Princess, Empress, Russian, curly coiffure, chemisette, high neckline, ruff, brooch, lace-edged fichu, nows, vee neckline, close sleeves, cuffs