In this article, a group of five preservice teachers and a teacher arranged to try a few activities at their campus day care. Together, they created and tested a series of learning centers involving rocks and minerals. Since minerals occur in such a wonderful variety of colors, they formed the basis for an engaging lesson on color sorting. This activity simulated one of the ways scientists identify minerals and gem--by color. Furthermore, in another activity, students explored rock colors and textures by matching rocks to cardboard egg-carton compartments painted with each rock's color and texture. In addition, as students conducted these activities, they learned about minerals and rocks in an age-appropriate way while practicing important skills that scientists use. They also exercised foundational mathematics skills and practiced fine-motor movements. (Contains 2 figures.)