A paper has been published this week which suggests that the surface of the planet Mercury may be comprised of cometary carbon. This means that carbon has littered the surface of Mercury, all of it from comets hurtling through space. In comparing Mercury to our own Earth-circling moon, the group responsible for this study suggest that 50 times as many carbon-rich micrometeorites impact the dark planet as do our own nearby space body. This has resulted, says the study, in approximately 3–6 wt% carbon at Mercury’s surface.
The darkness, therefor, could be "entirely alien", as the title of this article suggests. While the surface besides the carbon (from comets turned meteorites), isn't quite so resistant to reflecting light, the carbon is not all about bouncing beams.