Hey, congrats to your friend! It's always good to hear about a new member in training!
Our colors are maroon and white, and although we do not have an official mascot, most chapters I believe use a penguin (though my chapter here at UMaine uses a polar bear)... it'd be best to try to get in contact with another sister of your friend's chapter to find out. A lot of times we use our flower (white rose) as a symbol. Hope this helps, and tell her she can log on here and talk to other Gamma Sigs!