What gives bricks their different colors?

Building bricks come in a variety of colors, all of them handsome because they blend Jith the earth and the warm tones of the natural scenery. Bricks are made of baked clay and clays are mixtures of earthy minerals. Their mixtures vary from place to place. Most clays contain small or large amounts of iron compounds. Several factors may add color to this or that batch of bricks. But as a rule, the final color is decided by the amount of iron compounds in the basic clay. Most red bricks get their rosy hues because their clay had a high percentage of iron minerals. Clays with a scanty quota of iron compounds tend to produce lighter bricks of yellow, tan or buff. Sometimes light bricks are given a final flash of smoky firing ill the kiln. This darkens the iron minerals in the mixture and adds deep brown tones or rich dark reds to the finished bricks.  more