Here's what I said about it on GeekDad's first holiday gift guide:
The Elements: A Visual Exploration of Every Known Atom in the Universe
Even if this book weren’t absolutely gorgeous, it would still be a worthwhile investment because of how well it works as Coffee Table Education. This is when you leave a book lying around that is so tempting the kids pick it up and start learning stuff without even being asked! Based on author Theodore Gray’s amazing website, The Elements offers a double-page spread (or sometimes more than one) on each element, complete with lush photos of the raw material in its pure form, as well as in various incarnations, both common and rare. Delightful. Buy it on Amazon.