Opals are gems, yet are not crystals. Instead, opals are composed of amorphous quartz.
The New York Times has run an interesting book review entitled, 'In God, Distrust'. The reviewer takes a mostly positive position on Christopher Hitchens, author of 'God Is Not Great: How Religion Poisons Everything' (307 pp. Twelve/Warner Books.) I think that the book's title is a little over the top.