What describes the finest soil made up of particles less than 0.002 mm in diameter?

The finest soil, composed of particles smaller than 0.002 mm in diameter, is categorized as clay. This soil type is known for its small particle size, which contributes to its unique properties, such as high plasticity and the ability to retain moisture. Clay soils generally have excellent nutrient-holding capacity due to their high surface area relative to volume, allowing them to bind nutrients and water effectively.

In contrast, silt refers to soil particles that are larger than clay but smaller than sand, with a diameter between 0.002 mm and 0.05 mm. Sand consists of larger particles ranging from 0.05 mm to 2 mm and typically has good drainage but poor nutrient retention. Loess is a specific type of sediment that primarily consists of silt and is often wind-blown. While all of these soil types have important roles in the environment and agriculture, clay is distinctly defined by its particle size and corresponding physical and chemical properties.