I have some tortoise-shell sunglasses (shades of lighter to darker brown/black) but the lenses are green (Ray-Ban Wayfarers). I wouldn't think that they would make a person look old. At least I hope not. The theory here is that, generally speaking, the frames/lenses that one chooses should not only complement the shape of one's head, but also one's complexion. So as long as my hair stays brown, I am going to keep these in the rotation. They may not be as "classic" as the black ones... a la Blues Bros.-Tom Cruise in Risky Business-Ric Ocasek (or insert your favorite rocker)...but I like them on me. There are just so many combinations of brown frames/brown lenses that it would be hard to generalize. Certain pairings may give an oldish impression, I suppose. I always liked the Steve McQueen (Persol?) kind of look. Serengeti has some brown on brown stuff that I like as well.