This section reefers to the USDA Soil Textural
Classification System, it differs from other systems such
as ASSHTO, Unified, and PHI). For complete information go
to:
Material smaller than 2 mm diameter is called the fine
earth fraction, particles larger than 2 mm are rock
fragments.
The complete break-down of fine earth fractions are:
Very coarse sand: 2.0-1.0 mm Coarse sand: 1.0-0.5 mm Medium sand: 0.5-0.25 mm Fine sand: 0.25-0.10 mm Very fine sand: 0.10-0.05 mm Silt: 0.05-0.002
mm Clay: < 0.002 mm
