*pulls out copy of Indiana Jones and the Philosopher's Stone*
Indy discovers a Crystal Skull in British Honduras in 1933, which is repeatedly stolen from him throughout the book. The skull carries a curse: you will kill what you love. While not the true MacGuffin of the book, Indy is wary enough to keep a slight distance from the love interest of the book, Alecia Dustin. He finally recovers the skull at the end while avoiding the effects of the Philosopher's Stone (which turns out to be pure uranium), and the skull is stolen from the Italian museum he donates it to at the end. Leonardo Sarducci, the villain of the book, makes mention that the design of the skull is not Mayan, but possibly from an older civilization more advanced than the Mayans, but Indy brushes this off. The skull itself is described as a normal-looking human skull made of crystal.