Source - NASA Science News for July 11, 2013
Astronomers working with NASA's Hubble Space Telescope have deduced the actual color of a planet orbiting another star 63 light-years away. The planet is HD 189733b, and its color is cobalt blue. If seen directly, this planet would look like a deep blue dot, reminiscent of Earth's color as seen from space.
The complete article can be found here: http://science.nasa.gov/