Loess is a type of wind-blown sediment that consists mainly of silt-sized particles. It is typically yellowish or brownish in color and can form thick deposits in various regions around the world. Loess is known for its fertility, making it an important soil type for agriculture, especially in areas like the Great Plains of the United States and parts of China. The formation of loess occurs when strong winds carry fine particles from deserts or riverbeds and deposit them in nearby areas. This process can create extensive loess plateaus and cliffs, which are often characterized by their steep faces. Loess is also prone to erosion, which can lead to unique landforms and landscapes.