When was sidewalk chalk first invented?

Sidewalk chalk, as we know it today, became popular in the 20th century, but its origins can be traced back to the use of calcium carbonate and other natural materials for marking surfaces. While specific dates for "invention" are hard to pinpoint, the modern formulation of sidewalk chalk emerged in the 1930s when manufacturers began producing it in various colors and shapes for children's use. The evolution of chalk-making techniques and materials contributed to its widespread availability and popularity in schools and playgrounds.