Hmm, that is pretty fancy. The item and design itself aren't too serious, but going through Tiffany's is big time in my eyes. I mean if you'd bought it at Macy's for a hundred bucks it'd be no big deal, but Tiffany's is pretty high end.
Just my initial impression, otherwise it is a very nice gift, You could probably phrase it to be more of a friendship gift, like saying thanks for helping you through a rough time in your life.