The study of the composition, texture, and structure of the minerals in the clay from which pottery is manufactured. The purpose of ceramic petrology is to locate the source of the clay from which the pot was made. Ceramic petrology involves either heavy mineral analysis or petrologic microscopy, both of which require samples to be removed from the pot. Neutron activation analysis is also used. Results from these studies have far-reaching consequences for the study of early economic systems. Not only has it been shown that pottery and its contents were transported over long distances in antiquity, but also that the specialized manufacture and marketing of pottery started as far back as the first agriculture in Europe.