These objects have received little study, perhaps because edged tools and weapons have more intrinsic interest to collectors, but closer study of them might reveal something of domestic practices and toolmaking technology. There is no agreement upon their purpose or purposes, which may have included the processing of food, medicine or pigments, storage, arrow-production or fire-drilling. Visually, they may resemble omarolluks, a naturally occurring feature of sedimentary rock occurring exclusively in the Belcher Islands, an archipelago accounting for 0.25% of Hudson's Bay, whence they are thought to have been spread by glaciers.

Similar objects are associated with Celtic Europe and even Australia and Palestine. Some scholars insist the items are "false" artifacts, that is, their form results from natural processes rather than human activity. However, no one has yet described processes that might both produce such effects and also explain the distribution of the effects and the objects. Certainly air-bubbles in stone, broken open and eroded, could produce some of these phenomena. The objects are familiar in Illinois, Ohio, Indiana, Arkansas, Kentucky, Tennessee, Alabama and Mississippi, and occur elsewhere as well.

The pattern, size and number of concavities is not predictable, nor is material—impressions are found in soft sandstone and hard granite. Cupstones may exhibit a mixture of large and small indentations, perhaps indicating multiple uses over a considerable span of time. Indentations range from barely visible 1/16" to 6". Examination under magnification suggests the impressions were at least in some cases formed by rotary grinding. Typical impressions are of the simple pit type, though some cavities have been excavated to produce an opened-sphere type of pocket, by means and for reasons unknown. Very large specimens weighing several tons and with dozens of impressions several inches across are thought to be cult objects; they have been found throughout the Mississippi Valley.

There are several ethnographic accounts of the Native use of nutting stones in the historic times. One account says "the Virginia Indians in 1587 tells us that each household had stones for cracking nuts and for grinding shell and other materials." It goes on to say that "This statement would doubtless be equally true if applied at that time to almost any tribe inhabiting the section east of the Mississippi."

Early observers saw the processing of mast using stones, and one later recreation achieved similar results: nuts were placed, one at a time, on stone (an "anvil" stone") and then struck with a smaller "hammer" stone: “As nuts were cracked in this manner a pit developed in the lower stone; the pit deepened as additional nuts were cracked, and this facilitated the cracking process since nuts were held rather stationary in this 'seat.'”

The most likely interpretation seems that these artifacts represent a single technique of shaping or adapting stone for multiple purposes, some unguessed (for instance, the function of the smallest pits) and that the objects could be used by single or multiple individuals over long periods of time, and for various purposes. Indeed, the apparent randomness of their distribution may indicate that they were left lying as modified natural resources, whether with benevolent intent or because they did not represent a sufficient investment of time and labor to justify transporting them ("opportunistic" tools). More simply, perhaps the users intended to return to the same area during the next year's mast-gathering period.

The now traditional term "nutting stone" may be justified, as may "straightening stone" or "shaft-anchor" (for straightening arrow-shafts) within a larger class we might call "poculoliths," (<L. poculus, "small pocket," "cup"). While an equivalent to "pitted stone," the proposed term has the advantage of wider comprehensibility among international scholars as the worldwide distribution of the form becomes increasingly evident.

Nutting stones can be very similar in appearance to omars. Omars are naturally formed stones that have hemispherical bubbles in them.

North American pre-Columbian chronology – Adena – Alachua – Ancient Pueblo (Anasazi) – Baytown – Belle Glade – Caborn-Welborn – Calf Creek – Caloosahatchee – Clovis – Coles Creek – Deptford – Folsom – Fort Ancient – Fort Walton – Fremont – Glades – Glacial Kame – Hopewell (List of Hopewell sites) – Hohokam – Leon-Jefferson – Mississippian (List of Mississippian sites) – Mogollon – Monongahela – Old Cordilleran – Oneota – Paleo-Arctic – Paleo-Indians – Patayan – Plano – Plaquemine – Poverty Point – Prehistoric Southwest – Red Ocher – Santa Rosa-Swift Creek – St. Johns – Steed-Kisker – Tchefuncte – Tocobaga

Angel Mounds – Bandelier National Monument – The Bluff Point Stoneworks – Cahokia – Chaco Canyon – Casa Grande – Eaker – Effigy Mounds National Monument – Etowah Indian Mounds – Eva – Folsom Site – Fort Ancient – Gila Cliff Dwellings National Monument – Holly Bluff Site – Hopewell Culture National Historical Park – Kincaid Mounds – Kolomoki – Manitou Cliff Dwellings – Meadowcroft Rockshelter – Mesa Verde – Moorehead Circle – Moundville – Mummy Cave – Nodena Site – Ocmulgee National Monument – Old Stone Fort – Parkin Park – Pinson Mounds – Portsmouth Earthworks – Poverty Point – Pueblo Bonito – Rock Eagle – Rock Hawk – Salmon Ruins – Serpent Mound – Spiro Mounds – SunWatch – Taos Pueblo – Toltec Mounds – Town Creek Indian Mound – Winterville