The thermal mass of a wall, roof, or floor is directly related to its weight and to the specific heat of the material. The weight and specific heat are important to the energy performance of buildings and are recognized by most energy efficiency standards such as California's Title 24.
Another factor not measured by the Title 24 Standards, however, contribute to the performance of a masonry wall is the color. A lighter color masonry wall will be able to better reflect the solar penetration, however, the greater the heat capacity of the wall the less the color will matter. Color can also be used to enhance the appeal of a masonry structure.