I'm studying some introductory geology and this book turned out to be an excellent overview of all the various facets of the science. I guess a common alternative as a first book is "Teach Yourself Geology" but although this book is shorter it is better, I think, at summarizing what it's all about. It also has a lot of color images which are really essential for any geology book to be worthwhile. On the other hand, I would have preferred bigger images which would have been possible with a bigger book format (I took away a star for the small format).
I think if a high school student has an interest in rocks and minerals, this book would make a welcome present whereas something like the teach yourself book would be heavy going.