Information seeking is "a conscious effort to acquire information in response to a need or gap" in your knowledge (Case, 2007, p. 5). In the geosciences, physical samples such as cores, cuttings, fossils, and rocks are primary sources of information; they represent "the foundation of basic and applied geoscience research and education, and underpin industry programs to discover and develop domestic natural resources" (National Research Council, 2002, p.8). This dissertation investigates the information seeking behavior of geologists when searching for physical samples. It takes a unique approach by looking at physical objects as information sources, as opposed to past studies which focused on print literature (Bichteler & Ward, 1989; Joseph, 2001). Data collection was twofold. First I administered two questionnaires to state geological surveys. Thirty-five state geologists and 28 repository managers responded. The results capture an overview of these science data centers and their handling of collections of physical samples. State geological surveys were selected as they are a distinct type of facility which are similar to libraries. Like libraries, these institutions' missions dictate maintaining a collection as well as providing access to their diverse data holdings. In the second stage, I interviewed 15 geologists, primarily users of state geological survey collections. Responses highlighted various search behaviors which were used to develop a model of their information seeking behavior. Some behaviors were dependent on one's role within an organization, suggesting a division of labor in the research team. Many behaviors related to a researcher's knowledge of the domain, e.g., knowing where to look, who to talk to, and how to determine the quality of the information found. The most frequently used search process by interview participants was relying on their social network to recommend or locate samples. The results of this study suggest a number of recommendations and research opportunities for science data centers, including: 1) developing infrastructure which supports discovery and access, 2) further exploring the nature of task and role in searching, 3) developing training for searchers and curators, 4) developing standards for metadata creation related to physical samples, and 5) developing tools to aid in the search process. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]