Soft and fragile when dry, malleable on contact with water, set for ever by fire, clay influences living things like no other rock. From the Ganges delta to the Namibian desert, following these infinitesimal particles means discovering a material that gives birth to islands, nourishes forests and has accompanied humankind since the dawn of time.
In the middle of the Namibian desert, ephemeral rivers flow only after big storms; slowed by the dunes, they leave their mud behind, and the clay settles.
Its particles, around a micron in size, slide over one another: hence its malleability, and the fineness of detail it allows the potter.Eroded in the Himalayas probably thousands of years ago, tiny particles of rock travel down the Ganges to the sea. On contact with salt water, they attract one another and clump together, and from this mud a delta is born, a world half liquid, half solid. In the Sundarbans, the biologist Sourav Paul watches the mangroves, in their millions, gather clay around their roots and extend the mudflat from which new islands emerge. In Poitiers, Baptiste Dazas observes its architecture: sheets stacked like a deck of cards, so thin that one cubic centimetre unfolded would almost cover a rugby pitch, so many surfaces offered to water and to life. The soil scientist Daniel Richter, in the American Piedmont, even sees it being born from the acids produced by trees and microbes: “They are the fruit of life.”
Daniel Richter has been following clays from the depths to the surface for forty years, a journey that takes thousands of years.In the Bengal basin, it is no longer clear whether it is people who shape clay or clay that shapes people. In Kumartuli, the potters’ quarter of Calcutta, hundreds of artisans model no fewer than 10,000 statues. Sonatol Jelo considers clay his family. He needs calm when the time comes to do the eyes, for that is when the statue becomes the goddess incarnate. Many religions have humankind born of this material, on which people first began to write and which made them settle. In Kulpi, on the banks of the Ganges, hundreds of families mould and fire it: in a way, it dies to be resurrected as brick. The foreman Sailen Pramanik, who swam in the mud as a child, sometimes dreams of brickworks. Brick, he says, is “almost like my umbilical cord”.
One legend has it that the clay for the statues was gathered at the thresholds of brothels, where clients left their purity behind.
Between the clay dug from the riverbanks and the brick out of the kiln, it takes 25 to 30 days. Here, people say, “clay is money”.Between the treetops and the deepest groundwater lies the critical zone, a very thin layer that Daniel Richter calls the skin of the Earth. In Namibia, the sedimentologist Roger Swart follows the dust that the wind carries up to 800 kilometres, laden with the iron that the oceans lack and that stimulates plankton, at the base of a food chain of which we are part: “The desert gives life to the sea.” In Kaokoland, the entomologist Eugène Marais observes termites that dig down as far as 40 metres to find it. Yet the brick industry is among the most polluting in India. On the banks of the Ohio, the geochemist Martin Pentrak modifies clay to trap nitrates and hopes to make filters from it capable of cleaning rivers. Inhabiting the Earth may first of all require us to remember that we live on its skin.
The termites’ clay tower picks up variations in the wind and works like a lung: the colony renews all its air in two minutes.
Among the Himba, the same clay, taken from termite mounds, is used to build the walls of the small huts.
Himba women draw clay from the foot of termite mounds; when pregnant, they eat it to meet the mineral needs of their foetus.
Some animals are geophagous: they swallow clay to heal themselves, purify themselves or supplement their mineral intake.Clay still has many secrets to reveal to those who take the time to contemplate it.