When I looked at this scene of Maroon Bells, the words from the song "America the Beautiful" came immediately to mind. The song writer's wonderful words "...purple mountain majesty..." actually referred to another majestic mountain in Colorado, namely Pike's Peak. Regardless, the Rocky Mountains are so amazingly beautiful that I think the words can be used for any of the peaks.
Mountains tend to take on a purple tone during sunrises and sunsets. I am not sure what the scientific explanation is for the purple tint or, for that matter, any other color tints that mountains seem to take on. I believe that it has to do with a lot of variables, including the angle of the sun, and the amount of dust in the air to name two. Perhaps my love for mountains is because of the different "personalities" they take on when the light changes.