A:Answer Only Apple can give the best answer, but knowing a little about metal processing I MIGHT be able to give an educated guess. The material used in this keyboard is an "alloy " aluminum. To get the color, the chemistry and manufacturing process is different in this metal, versus the silver aluminum appearance on their other products including the i-Mac. It actually started with the i-Phone, then was used on the i-Pad products, and more recently the i-Mac Pro. This keyboard and mouse now come in silver and space gray giving it a great appearance.
