Sand: an aggregate of rock fragments. Sometimes including loadstone, tinstone, or more rarely gold dust. Diameter: 2 to 1/16mm
A very clear definition indeed. In short, the sand came from fragmented rocks and was interemediate between clay and pebble. But simply calling it an intermediate substance did not provide a really satisfactory explanation. Why was it that isolated deserts and sandy terrain came into existence through the sifting out of only the sand from soil in which clay, sand, and stones were thoroughly mixed together? If a true intermediate substance were involved, the erosive action of wind and water would necessarily produce any number of intermingling intermediate forms in the range between rock and clay. However, there are in fact only three forms that can be clearly distinguished from one another: stones, sand, and clay. Furthermore, sand is sand wherever it is; strangely enough, there is almost no difference in the size of the grains whether they come from the Gobi Desert or from the beach at Enoshima. The size of the grains shows very little variation and follows a Gaussian distribution curve with a true mean of 1/8mm.
Because winds and water current flows over the land, the formation of sand is unavoidable. As long as the winds blew, the rivers flowed, and the seas stirred, sand would be born grain by grain from the earth, and like a living being it would creep everywhere. The sands never rested. Gently but surely they invaded and destroyed the surface of the earth.