These pieces have a monumentality and physical size that had no precedent in contemporary ceramics. In this case, as was to be true for each new series Mason embarked on, a whole new technology had to be evolved or invented to execute the new pieces. Due to the size limitations of the kiln, the forms had to be fired in sections and the pieces later assembled on the wall. Originally constructed on the floor, they recall the harsh, rocky terrain of the desert.〔Haskell, Barbara. "John Mason, A Chronology", ''John Mason Ceramic Sculpture''. Pasadena: Pasadena Museum of Modern Art, 1974, p.6〕

The ''Firebrick Sculptures'', begun in the early 1970s, reveal a shift in Mason’s work away from an involvement with materials and technique toward an involvement with the conceptualization and systematization of a piece that is removed from its actual realization. While maintaining an association with the ceramic tradition – firebricks are made of ceramic material and are used for the construction of kilns – their neutral color and standardized form make it possible to conceive of and execute large-scale geometric configurations of stacked bricks, such as ''Hudson River Series VIII'' (1978), in a variety of mathematically plotted arrangements. These works cannot be perceived as single objects, and move into areas of spatial experience, visual perception and illusion, and architectural site-oriented installations. It is such systematized manipulation and exploration – in both ceramic and non-ceramic materials – that continue to direct Mason’s work.〔