All dirt is basically made of three different kinds of particles. These are clay, sand, and loam. Clay is very fine, small inorganic particles, worn down from rock.
Sand is bigger, coarser particles, also from rock, often quartz or silica.
Loam is organic particles. Down where the purple spot is, that would be good clay for making pottery . Over by the green dot, that's sand that you can melt down into glass . You need animals to pull the plow. A lot of northern European soils are like that, and also the soil in river valleys like the Nile .