A student from last year came up to me when I was on duty, grabbed my left hand, and carefully examined my wedding ring...

Ally:  Nice metamorphic rock.

Mrs. B:  Where did you learn that?

Ally:  Uh...from you...last year...during our geology unit.

Mrs. B:  So you were paying attention sometimes!

Ally:  Oh, I always pay attention when it comes to diamonds!