High iron levels in the clay give the bricks a beautiful reddish color while adding to their overall hardness.
當時彰化縣的磚窯廠數高達六十幾家，花壇便占一半以上。磚塊的先決條件要磚面好看、硬度夠，而八卦山的紅棕土略帶黏性且雜質低，是磚瓦窯燒的優良原料，內含豐富的鐵質，更有助於燒出色澤紅潤、硬度佳的上品。