An interesting custom that can be found in Equatorial Guinea is the eating of chalk. I observed it when I went to the market for the first time and found it for sale at more than half the stands. When I asked the woman who was selling it what it was for, she didn't really have an answer for me. She did tell me that it helps the digestive tract, and is really good for pregnant women. She also said it can be ground up into a powder and applied to the skin to make it healthier. Several other times I have asked nationals about this interesting custom, and no one really has a definitive answer. So, I've determined that it is just a cultural event.
I then was determined to try and do some research on it and find out more information. This is what I found:
The term is called geophagia or geophagy. It is the practice of eating earth or soil-like substrates such as clay or chalk. It can be found most often in rural or preindustrial societies among children and pregnant women. There is also a mental disorder that involves the ingesting of dirt or other non-edible items – this is not what this is.
I also found that geophagia is nearly universal around the world in tribal and traditional rural societies – although it has not been documented in Japan and Korea.
In Africa, this custom is found in Gabon and Cameroon and is known as kalaba. In Equatorial Guinea it is known as calabachop. It is said (according to my source) to be eaten for pleasure or to suppress hunger.
An interesting note is, clay minerals have been reported to have beneficial microbiological effects such as protecting the stomach against toxins, parasites and pathogens.
So I bought some, and we all tried it. It is an interesting experience indeed.