The lab described in this article was developed to satisfy two major goals. First, the activity is designed to show students the proper techniques used to identify the seven characteristics of all minerals. Second, the lab gives students a glimpse into the life of a professional field geologist. The author has students complete this lab at the end of a unit on minerals. Eighth graders typically learn the ways that minerals form, the traits that an object must possess in order for it to be considered a mineral, and the methods of identifying the name of a mineral using its traits. "You Be the Geologist" is an adaptation of the traditional, teacher-centered method of mineral identification. This activity requires students to mimic the work of a geologist attempting to identify unknown mineral samples. To do this, students work cooperatively with a partner to decide the best way to identify each mineral sample.