• (n.) The act or habit of eating earth. See Dirt eating, under Dirt.
Ge·oph'a·gism noun [ Greek 
Geophagism is the practice of eating some kind of earthy matter, such as rock or chalk. It is most common among non-industrialised races, and was once thought to allay hunger. However, new evidence suggests that some peoples obtain valuable minerals in their diet from geophagism, as those minerals are not available in their normal food, and as such...
geophagism The eating of soil or clay.