rustication (rŭstĭkāˈshən) [key], in building construction, method of creating textures upon masonry wall surfaces, chiefly upon those of stone, by projecting the blocks beyond the surface of the mortar joints. Each joint thus lies in a channel or in a V-shaped groove, between adjoining stones, and a separating shadow line is produced. The degree of projection, whether slight or bold, permits varying effects. The Romans occasionally built rusticated walls. This device was used by Renaissance architects in the palace facades at Florence, a favorite treatment being that of a ground floor with stones of strong projection and roughly textured surface, surmounted by upper stories in which both forms were more refined. Often columns and pilasters also were rusticated. The basement story of the Pitti Palace (mid-15th cent.) exhibits a celebrated example of rustication, some of its enormous and roughly quarried blocks of stone projecting as much as 2 ft 6 in. (76.2 cm) beyond the surface of the joints. The garden architecture of the Italian baroque villa shows many grotesquely textured examples. Rustications also appeared frequently in the Georgian style and in American Colonial architecture.