The three types of rock particles that make up soil are sand, silt, and clay.
Sand particles are the largest, with a diameter of 0.05 to 2 millimeters.
Silt particles are intermediate in size, with a diameter of 0.002 to 0.05 millimeters.
Clay particles are the smallest, with a diameter of less than 0.002 millimeters.
The relative proportions of these three types of particles in soil determine its texture. Soils with a high sand content are coarse-textured, while soils with a high clay content are fine-textured. Soils with a balanced mix of sand, silt, and clay are loam soils, which are considered to be the most fertile.
Soil particles are constantly being weathered and eroded, and new particles are being formed. This process of weathering and erosion is what creates soil. Soil is essential for life on Earth, as it provides plants with the nutrients they need to grow.