At first glance, nano and Earth seem about as far apart as one can imagine. Nanogeoscience seems to be a word connecting opposites. But to a growing number of Earth scientists, this term makes sense. Although relatively difficult to detect and study, natural nanomaterials are ubiquitous in nature. Their properties are often different (sometimes dramatically different) from those of the same material at a larger size. In many cases, larger equivalents do not even exist. By understanding natural nanomaterials, we can acquire another perspective from which to view Earth's chemical and physical properties. Important insights into local, regional, and even global phenomena await our understanding of processes that are relevant at the smallest scales of Earth science research.