Although we do not know exactly when gypsum began to be used by human beings, the first historically recorded use of calcium sulfate dihydrate was by the Egyptians, who used it in construction, in the manufacture of pottery, and in bandages for mummifying.
The ancient Greeks called this material gypsos. The term was transformed into gypsum in Latin, through which it spread across Europe and into the Iberian peninsula, developing into Spanish and Portuguese gis, Catalan guix, and Galician xiz. The word then crossed the ocean, taking root in Mexico, where it is still the common word for chalk. The same substance was also used in pre-Hispanic Mexico. Curiously enough, the Spaniards learned the Nahuatl word tizatl (literally, “white earth”) in colonial times, and now tiza is the usual word for chalk in peninsular Spanish.
As we can read on the webpage of the SNTE (the Mexican teachers’ union), chalk was for many years an indispensable tool in the classroom, as teachers spent hours writing on blackboards of slate or wood. Their hands would be thoroughly white by the end of the day. In more recent times, chalk has been replaced by water-based markers and blackboards by “whiteboards,” or even in some cases by electronic surfaces.
Chalk is a piece of participative public art by the duo Allora & Calzadilla. The project began in 2002 in a public square in Lima, Peru, as part of the Bienal Iberoamericana de Arte. Since then, it has been presented in numerous places around the world.