What is the Difference Between Sand Silt and Clay

The main difference between sand silt and clay is their particle size. Sand particles are larger in size while clay particles are extremely fine, and silt particles are somewhere in between sand and clay particles.

We determine the soil texture of a place by analyzing the mineral particles it contains. Sand, silt, and clay are the main mineral particles in the soil that affect its texture. These particles are made from rocks broken down by climatic and environmental conditions over thousands of years.

Key Areas Covered

1. What is Sand 
     – Definition, Features
2. What is Silt 
     – Definition, Features
3. What is Clay
     – Definition, Features
3. What is the Difference Between Sand Silt and Clay
    – Comparison of Key Differences

Key Terms

Clay, Sand, Silt, Soil

What is Sand

Sand is a loose granular material formed by the disintegration of rocks. It consists of particles of rocks and minerals like silicon dioxide. Sand particles are smaller than gravel but larger and coarser than silt. In fact, they are the largest and coarsest mineral particles in the soil. Each particle of sand is visible to the naked eye.

Coarse sand particles range from 2.00 to 0.05 mm in diameter and can feel gritty when you rub them between your fingers. Even when you stick it together in your hand, it will feel light and crumbly. These relatively large particle sizes can increase oil aeration, improve drainage in tight soil and support plant growth. Moreover, sand particles can be angular, round, flat, or elongated. In addition, the texture may be rough, smooth, or polished.

What is Silt

Silt is a dust-like sediment material transported and deposited by water, ice, and wind. It’s a granular material with a particle size between sand and clay. The particle size of silt ranges from 0.002 and 0.06 mm. Furthermore, silt typically has a mineral origin of quartz and feldspar.

When dry, silt may feel similar to flour. When wet, it becomes smooth mud, and you can form shapes in your hand. However, when it’s very wet, silt can blend seamlessly with water and form very fine, runny puddles of mud. Moreover, due to its fineness, silt has low plasticity or no plasticity at all.

What is Clay

Clay is a type of extremely fine-grained natural soil material containing clay minerals. These particles are the finest of all soil particles and are usually smaller than 0.002 mm. Clay consists of microscopic and sub-microscopic particles that come from the chemical decomposition of rocks.

The fine grains of clay makes the soil cohesive. Clay particles readily stick together and form a sticky texture when they are wet or dry. Clay soil can hold a good amount of water when we compare them with sand and silt. It expands when it is in contact with water and shrinks when getting dry. Moreover, different forms of clay have varying degrees of plasticity, which is the ability to be stretched or bent. The more plastic a clay, the more workable it is, i.e., easier to mould into different shapes.

Difference Between Sand Silt and Clay

Definition

Sand is a loose granular material formed by the disintegration of rock, while silt is a dust-like sediment material transported and deposited by water, ice, and wind. Clay, on the other hand, is a type of extremely fine-grained natural soil material containing clay minerals.

Particles

Sand has coarse and larger particles, while clay has extremely fine particles. The size of silt particles ranges between the size of sand and clay particles.

Size Range

The particle size of sand ranges from 2.00 to 0.05 mm, while the particle size of silt ranges from 0.002 and 0.06 mm. The particle size of clay, on the other hand, is lower than 0.002 mm.

Plasticity

Moreover, sand has no plasticity, while silt has very low or no plasticity and clay has high plasticity.

Conclusion

The main difference between sand silt and clay is their particle size. Sand particles are larger in size while clay particles are extremely fine, and silt particles are somewhere in between sand and clay particles.

Reference:

1. “Sand? Clay? Loam? What Type of Soil Do You Have?” Gardeners, Available here.
2. “Silt.” National Geographic Society, 9 Oct. 2012, Available here.

Image Courtesy:

1. “A scene of river sand” By Thamizhpparithi Maari – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Silt in the River Avon – geograph.org.uk – 135173” By Linda Bailey (CC BY-SA 2.0) via Commons Wikimedia
3. “Clay Soil” By Krish Dulal – Own work (CC BY-SA 3.0) via Commons Wikimedia