Rock flour

Rock flour, also known as glacial flour, is made when glaciers grind rocks as they move. Glaciers are giant walls of ice and snow that move very slowly over land, carving out valleys and rocks in their path. As glaciers move over rocks, they break them up into tiny pieces, creating a powder-like substance called rock flour. Rock flour can be used in many ways, including for building projects, for gardening, and for filling in low-lying areas where water might collect. It even acts as a natural sunscreen when spread on the ground!