What roman author described the technique of Opus quadratum?
Opus quadratum Opus quadratum is an ancient Roman construction technique, in which squared blocks of stone of the same height were set in parallel courses, most often without the use of mortar. The Latin author Vitruvius describes the technique.
Opus albarium Opus albarium is the Latin name for a refined type of plasterwork used in the interiors of houses, consisting of a special stucco incorporating marble dust, then beaten compact with rammers: the technique is described by Vitruvius (VII.3.4-11). Varro states ("R.R." I.59.2) that such wall coatings make buildings cooler.