It was dug in a solid mass of tufa nearly ten mtres thick, which had been formed in the centuries anterior to Csar.
The material is generally lava, but tufa and limestone are also found.
The rocks in the vicinity are all tufa, and some of the springs break out close to the cold water of the lake.
In style and construction this colonnade belongs to the tufa Period (p. 40).
In those parts of the Campagna where basalt rather than tufa becomes the usual material, as at Prneste, we find polygonal masonry.
The colonnade about the court was built of tufa, and coated with white stucco.
The substruction of this temple, which has been laid bare, consists of tufa cased with travertine.
The Doric columns were of tufa, coated with fine white stucco.
Most of the churches and palaces and houses of Orvieto were also built of tufa.
tufa is found all over the Campagna, and is of volcanic origin.
"a porous rock," 1770, from Italian tufa "tufa, porous rock," probably from Latin tufus, tophus "loose, porous volcanic rock," said to be an Oscan-Umbrian loan-word.