why is the moon gray? Options

[tfisher]

Really this applies to a lot of the solar system worlds, just the moon is the nearest and most visible. Why is it gray? I'm thinking there are two contributing possibilities :

(1) it looks gray because human vision is limited to distinguishing only a narrow range of the spectrum; if we could see a wider range of colors it wouldn't be so gray.

(2) it really is gray, even well beyond the range of human vision. This is because it is made up of gray rock, which doesn't have interesting spectral features really at any part of the spectrum.

My inner seven-year-old is begging to know "why". A bit of googling seems to indicate that (2) is more of a correct answer than (1) -- at least the only colorful images I can find seem to be forced false-color by some processing to give extreme exaggeration to tiny color differences. Is that right? Can anyone elaborate?

[Phil Stooke]

Take a good close look at a gravel bar in a river bed, or a pebble beach, or similar kind of collection of rocks... now, I'm saying that based on the kind of mixed rock areas I'm most familiar with, but I realize that in some places you could look at those things and see only one kind of rock. But in many places, look at a large collection of little rocks and you'll see a wide variety of shades and colours. Red, yellow, white, black, greenish, brown and so on. But step back and the whole beach, or bar, the whole pile of little rocks, looks grey. It's a mixture. On the Moon there's less variation to begin with. There will be white minerals, black minerals, a few that are slightly different, and then maybe a few coloured glasses, a bit green or orange. But mix it all together and the effect will generally be just grey again.

Phil