Palazzo dei Diamanti is a palace in Ferrara, northern Italy. It is one of the most famous palaces in Italy, as well one of the most influential examples of Renaissance European architecture.
Designed by Biagio Rossetti, it was built starting from 1493 by order of Sigismondo d'Este, brother of Duke Ercole I, in 1492. The most striking feature is the bugnato of the exterior walls: it consists of some 8,500 white (with pink veins) marble blocks carved to represent diamonds, whence the common name.
The palace today houses the National Gallery of Art in Ferrara (Pinacoteca Nazionale) and is frequently seat of exhibitions.