Why is concrete gray?
First of all, concrete can be ordered in many colors. The natural color of concrete is gray because the color of the cement used to make it is typically gray. Now, the reason the cement is gray has to do with the manufacture of Portland Cement. In cement manufacturing, Iron Ore is used as one of the main constituents, and Iron Ore is black in color, so when it is combined and melted with the other materials it tints the cement gray.
