Soil Size Classification

Dateline: 06/07/99

The size of soil particles determines their name. This chart provides names along with the standard diameter of the particles for both U.S. and International classification systems.

Particle	American Diameter	International Diameter
Clay	< 0.00008" / < 0.002 mm	< 0.002 mm
Fine Silt	0.00008 - 0.00024" / 0.002 - 0.006 mm
Medium Silt	0.00024 - 0.0008" / 0.006 - 0.02 mm	0.002 - 0.05 mm
Coarse Silt	0.0008 - 0.002" / 0.02 - 0.05 mm
Very Fine Sand	0.002 - 0.004" / 0.05 - 0.1 mm
Fine Sand	0.004 - 0.01" / 0.1 - 0.25 mm	0.05 - 0.2 mm
Medium Sand	0.01 - 0.02" / 0.25 - 0.5 mm
Coarse Sand	0.02 - 0.04" / 0.5 - 1.0 mm	0.2 - 2.0 mm
Very Coarse Sand	0.04 - 0.08" / 1 - 2 mm
Gravel/Stones	> 0.08" / > 2 mm	> 2 mm

 

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