Techniques for correlating a depth of drill bit cuttings include circulating a drilling fluid into a wellbore during a drilling process to form the wellbore in a subterranean formation; circulating a portion of uniquely identifiable particles from a container into the drilling fluid during the drilling process; circulating a return drilling fluid that includes the drilling fluid, cuttings from the subterranean formation, and the uniquely identifiable particles; separating the drilling fluid from the cuttings from the subterranean formation and the uniquely identifiable particles; capturing at least one image of the separated cuttings and the uniquely identifiable particles; and determining, based on the image, a depth of the subterranean formation.