Rock and mineral labs are fundamental in traditional introductory geology courses. Successful implementation of these lab activities provides students opportunities to apply content knowledge. Inquiry-based instruction may be one way to increase student success. Prior examination of published STEM labs indicates that geology labs, particularly rock and mineral activities, are often constructed at low levels of inquiry (i.e., students are provided context throughout each step of the scientific process rather than constructing their own knowledge). This could be related to instructor concerns about the time needed to implement inquiry-based labs. Here, 36 instructor-generated rock and mineral labs available through the Teach the Earth (TTE) collection are assessed using an inquiry rubric adapted from Ryker and McConnell and a newly developed utility rubric. For the activities within these labs (n = 55), inquiry levels ranged from confirmation (7%) to open (16%) with most identified as structured (58%). Lab activities from the TTE collection are generally more inquiry-based than previously published activities. Lab utility scores ranged from 18-29 on a 10-30 scale, where lower values indicate a greater difficulty of implementation. One particular challenge for these labs may be ease of grading, the category rated most often as having low utility. No significant correlations (p > 0.05) were identified between the inquiry and utility scores, contradicting the idea that increasing inquiry comes at the expense of utility. The rubrics utilized in and developed for this study provide researchers with beneficial tools for exploration of laboratory activities on other topics, or in different disciplines.