Is there a book out that is good for IDing stone. Kind of like the books you can get for IDing trees, brids,ect.... I just don't know what the stone looks like that works good for knapping. Would be nice to have a book to see what the outer crust on some of these stones looks like so I don't go out busting rocks apart to see the inside of them. Also is there a list of stones good for knapping on the site?