We investigated the use of iconic and deictic gestures during the communication of spatial information. Expert structural geologists were asked to explain one portion of a geologic map. Spatial gestures used in each expert’s response were coded as deictic (indicating an object in the conversational space), iconic (depicting an aspect of an object or event), or both deictic and iconic (indicating an object in the conversational space by depicting an aspect of that object). Speech paired with each gesture was coded for whether or not it referred to complex spatial properties (e.g. shape and orientation of an object). Results indicated that when communicating spatial information, people occasionally use gestures that are both deictic and iconic, and that these gestures tend to occur when complex spatial information is not provided in speech. These results suggest that existing classifications of gesture are not exclusive, especially for spatial discourse.