Moon is not as colorless as you can suspect. When you take good quality picture moon with color camera you can postprocess the frame to saturate the colors. Then you will notice some colors of our not-gray-anymore satellite. There are two dominant hues. Red/yellow indicates iron related content, like iron oxide FeO for example. Another color occurs in darker regions with lower reflectance. It is related to titanium presence, and this component shifts the color of the mares from red to blue.