Pipestone is the generic name for a wide variety of soft, fine-grained and easily carved, slightly metamorphosed rocks such as argillite, flint clay or catlinite. These stones are visually similar and typically red, but range in color from purple to near yellow; and they are not mineralogically identical. Each type of pipestone shares a basic but varied composition of diaspore, kaolinite, muscovite, pyrophyllite and occasionally minor amounts of quartz.
Pipestone has been used by different Native American societies for at least 3,000 years, as the raw material for carving elite and sacred objects. Some classes of artifacts that were frequently made of pipestone include the calumet pipe in the 16th and 17th centuries AD; Mississippian period Cahokia-style figurines, between AD 1100 and 1200; and Hopewellian pipes dated to the Middle Woodland period (~50 BC-AD 250).
Up until the last decade or so, the similarities between the raw materials, and the lack of systematic investigation into their varied geological histories, have made understanding the differences between pipestones and where they come from a complex puzzle indeed. Research over the past decade or more, primarily led by Thomas Emerson at the Illinois State Archaeological Survey (ISAS), has been focused on identifying the source quarries for different pipestone objects found on archaeological sites, and for developing and testing nondestructive methods to tie archaeological artifacts to their raw material sources.
At least seven red pipestone sources have been studied by the ISAS team to date, in Minnesota, Kansas, Illinois, Ohio, Missouri and Wisconsin. This essay explores the work accomplished by Emerson's team, and the current archaeological interpretations of some of the archaeological materials made of pipestone.
