Which soil particle is the smallest?

• A. Clay
• B. Gravel
• C. Sand
• D. Slit

Answer: (A)

Soil particle size is ranked from largest to smallest as gravel, sand, silt, and clay. Clay particles are extremely tiny—typically less than about 0.002 millimeters in diameter—making them the smallest of the set. That tiny size gives clay a very large surface area relative to its volume and a tendency to cling together, which is why clay soils feel sticky and compact and hold a lot of water and nutrients. Sand particles are larger, about 0.05 to 2 millimeters, giving a gritty texture. Silt sits between them, roughly 0.002 to 0.05 millimeters, smaller than sand but larger than clay. So the smallest particle among these options is clay.