What form of Judaism (details inside)?

If I sound ignorant here, I’m truly sorry.

My girlfriend and I were at the airport coming home from New York, yesterday and we came across this girl (I would say that she was in her early to mid twenties) wearing a long, black/coat dress (?) and a silver necklace (with a particular design). She was holding a small book of some sort and reading it/praying while rocking forward and back. She actually had two different books. One white and one black.

The poor girl looked as nervous as heck because we were about to bored the plane. She also had the most beautiful, hypnotizing eyes and when she looked at you, it was as if she was looking into your soul (if you believe in that sort of thing =)).