According to the Unified Soil Classification System (USCS), a soil grain with a size greater than No. 200 sieve opening but less than No. 4 sieve is classified as:

The Unified Soil Classification System (USCS) categorizes soil particles based on their size, which is essential for understanding their behavior and suitability for various engineering applications. A soil grain that falls within the size range greater than the No. 200 sieve opening (which retains particles smaller than 0.075 mm) but less than the No. 4 sieve (which retains particles larger than 4.75 mm) is classified as sand.

Sand particles are typically between 0.075 mm and 4.75 mm in diameter. This size allows for good drainage and air circulation, which are important characteristics in construction and geotechnical contexts. The classification as sand is significant because it directly affects the properties of the soil, such as its strength, compressibility, and permeability.

Silt and clay, on the other hand, represent finer particles—silt is smaller than 0.075 mm but larger than clay particles, which are even finer. Gravel refers to larger particles that exceed the 4.75 mm threshold. Understanding these classifications helps engineers determine appropriate construction practices and soil management strategies.