I read a story in 7th grade that had to do with people going to Mars to colonize it. I remember the story being very eerie in tone. At first the landscape on Mars was very inhospitable, but slowly they terraformed it so that it had springs, grass, etc. Over the course of their stay, though, they began to slowly change -- physically and mentally. I don't remember much else about it except the ending, in which I think one of the characters looks into a pool of water and notices he looks just like a Martian, complete with golden(?) eyes.
I'm also not sure if this was an excerpt from a larger novel or if it was indeed just a short story. It was in one of those huge literature books which might've contained either.
It was one of the first stories that made me realize the power and beauty in writing, so I'd very much like to find it. Any pointers are appreciated!