“‘As its name implies, the Chicago Common brick is both local and ever-present in the city. Owing to its low cost, high strength, irregular colouration and unequal dimensions (no two bricks are identical) it was the brick of choice for alley façades, [though] never street fronts, from 1871 through 1981, when it was last manufactured,’ the duo adds.”
Pei-Ru Keh, "Norman Kelley Designs Aesop Chicago Using Reclaimed Bricks," Wallpaper*, May 31, 2016.