The creature in the crystal / Darke, J. A

Even in tenth grade Val is still somewhat fascinated by anything to do with the supernatural, so when her "weird" cousin Veronica comes for the long weekend with a unique Ouija board, a bag of crystals, and a book of spells, Val is tempted--but when the nightmares start she begins to fear that Ronnie's love of the occult has woken up something dangerous.

Val, who has always loved the supernatural, jumps at the chance to read a book of spells and use the strange gems and Ouija board her cousin Ronnie brings over for a long weekend--however, Ronnie's sense of spooky fun may be too much even for Val, and soon Val's old nightmares and fears come back to haunt her in real life.