So I downloaded that game called "Universe Sandbox 2" and i have had a lot of fun with it. There are some things missing but the developers are updating it regularly. 
 

Anyway, I was looking at Mercury and it looked like this 

 

 

 The colour seemed off because I saw a picture of Mercury that was taken by "MESSENGER" back in 2008 and it looked like this (second image).

 

 

But then I decided to look at NASA's pictures of mercury aaaand... 

 

 

Sorry if the pictures are too big. I know that Universe Sandbox is not very accurate simulation but i have also heard that NASA uses CGI most of the time. So how does Mercury really looks like? The image MESSENGER took is an enhanced coulour image so to be honest i have no idea what's real anymore.

 

Without the source for the images, it is hard to say. I would guess that the last one was enhanced to show the presence of some particular wavelength or compound. 

Described as a false color image composite.

https://apod.nasa.gov/apod/ap130612.html

Most vivid colors look to be from the IR and UV ranges.

Probably first couple of images posted would be closer to true.

Websit on this

Cornell should be pretty reliable. I would have thought brownish if it had a lot of iron. But basically rock-colored.

Looks like the first link in each section is real-color, others are grayscale or false colored.