How do you call this in your language. In English it is identified as Calabash Chalk, in French it is called mabele, la craie or argile.

In Africa, Calabash Chalk is recognized by various names: Lingala in Congo, ebumba in Uganda, and in Ghana it is known as shilè, while in zulu (South Africa) it's called umcako.

The Igbo, Bini/Edo and Efik/Ibibio people of Nigeria refer to Calabash Chalk as Uzu, Eko and Ndom respectively.

Wikipedia describes Calabash Chalk as a kind of white clay from the river, eaten and used for the treatment of diarrhea, or as a whitewash, and rubbed on the body for decoration or against heat rash.

Calabash Chalk is native to Africa, particularly in Nigeria.

Calabash Chalk is commonly called in English Calabar Stone apparently because of its high deposits and usage among Efik/ Ibibio, the fourth largest ethnic group in Nigeria, especially during the Old Cross River State, Calabar as the State Capital.

This material appeared to have been lost but recently I ran into its huge deposit at a construction site in the heart of Uyo, the Akwa Ibom State Capital, formerly the Mainland part of the the Old Cross River State.

I observed one lady picking the material and was moved to ask her, What is it for?
I realized she was packing them for sale. What a huge business opportunity!
So do you need one? Then I am at your service.

But here is a brief information on the composition and usage of this material.

Although Calabar Stone can be prepared artificially by combining clay, sand, wood ash and salt, it occurs naturally composing of fossilized sea shells.

The major component is aluminum silicate hydroxide that comes from the kaolin clay group, making Al2Si2O5(OH)4 its possible formula.

It is also understood to have very high concentrations of lead.

The European Union recommends (Commission Regulation, 2001) that the amount of lead in food should not exceed 1 mg/kg, however the amount of lead contained in calabash chalk has been reported (Codex Committee of Food Additives and Contaminants, 2003) to be between 10–50 mg/kg. This makes it dangerous.

In addition, its composition may also include: aluminum, persistent organic pollutants, silicon, alpha lindane, endrin, endosulfan 11, arsenic, and chromium.

###As Geophagia ###

Calabar Stone is a geophagic material commonly consumed in West African countries for pleasure, and by pregnant women as a cure for nausea. The practice, known as Geophagia, involves eating the earth, including soil and chalk and can be associated with religious beliefs.

The practice of eating calabash chalk is observed by both sexes and different age groups of people of African descent, for the purpose of pleasure.

It is prevalent among women, predominantly during pregnancy, who claim it prevents vomiting, over-salivation and nausea. Calabash chalk is also used to make facial masks and soaps.

But beware of health risks. This is because when geophagical materials come in contact with digestive fluids, they have the potential of releasing clinical or sub-clinical toxic effects on an individual.