"Mineral Detectives!" is one of eighteen lessons in the "Private Whys?" integrated science unit, which uses a guided inquiry investigation to teach students in grades three through five about the role of minerals in our lives. The University of North Texas developed "Private Whys?" with funding from the Copper Development Association. This lesson can easily be implemented in the classroom, and the entire unit can naturally be integrated into existing elementary school curricula. (Contains 4 figures.)