The history about the historic tiara of the Duchess of Ratibor-Corvey :

Heart shaped diamond Ornament Tiara Marie Duchess of Ratibor-Corvey Large diadem with palmette in heart-shaped elements with diamonds. As base a double diamond hoop with large solitaires, in between leaf-shaped small motifs, lily-shaped, between the large elements.
The gallery set in gold. All motifs are wearable as brooches Jeweler Kobert Vienna 1860.

more details:

Duchess of Ratibor Corvey Honeysuckle Diamond Tiara| Marie Herzogin von Ratibor-Corvey Palmetten Diamant Diadem | Royal Jewel History Jewels Historic Jewellery
Marie Herzogin von Ratibor-Corvey Palmetten Diamant Diadem | Historischer Schmuck und Juwelen der Herzöge Ratibor-Corvey