The Moonstone by Wilkie Collins
There is a beautiful diamond - with a terrible curse. When Rachel Verinder is given the Moonstone - a large Indian diamond - on her eighteenth birthday, she is delighted to show it off at her celebrations. But that very night, the jewel is stolen from her bedroom. As suspicion falls on each member of the party, the curse of the diamond strikes - and ill-luck threatens to destroy them all. Will the noted detective Sergeant Cuff be able to solve the mystery? Or will the strange case of hypnotism, opium and Indian jugglers defeat even his brilliant mind?