Dark Magick

Dark Magick is a novel about a small town where everyone is either involved in witchcraft or has the 'powers' to be involved in it. This book was written by Cate Tiernan and is part of her Sweep book series.

Warning: Wikipedia contains spoilers.

Dark Magick, which is actually the name of a store in the book, is a story about a girl, Morgan, and her boyfriend Cal, who have attempted to kill a schoolmate named Hunter near a cliff, stabbing him with an athame. Through her powers and those of Hunter's cousin Sky, Morgan runs into surprise after surprise. Everything going on will affect her life as well as Cal's.