Pietra serena


Pietra serena is a gray sandstone used extensively in Renaissance Florence for architectural details. It is also known as Macigno stone. The material obtained at Fiesole is considered the best and it is also quarried at Arezzo, Cortona, and Volterra.
Examples of its use in Florence include the interior pilasters, entablatures, and other decorative elements of Brunelleschi's Pazzi Chapel and Michelangelo's Medici Chapel.

Physical traits

Pietra serena comes out of the ground as a blue-gray color. Due to a chemical reaction in the stone, it turns into red. This is due to oxidization in the clay matrix of the stone. Pietra serena has a very limited durability. This has led to problems with conservation efforts. This durability is also the reason why it is very workable.

Quarries

Pietra serena was very popular in the Renaissance, and because of this the quarries where the stone was found were exploited. Depending on the quarry, the grain size of the stone varies. Trassinaia was the main quarry used in the construction of Brunelleschi's Pazzi Chapel.