What is the size of the clay particle according to the USDA

2.0
Very coarse sand

 0.5-   1.0
Coarse sand

0.25-0.5
Medium sand

0.10- 0.25
Fine sand

0.05- 0.10
Very fine sand

0.002- 0.05
Silt

<0.002
Clay

🛑Additional Information
Particle Size Distribution: Measurement Techniques
There is a wide range of instrumental and other methods of particle size analysis available. Some of the more common methods are:
1. Sieve Analysis
2. Sedimentation Methods
3.Elutriation Techniques
4. Microscopic Sizing and Image Analysis
5. Electrical Impedance Method
6. Laser Diffraction Methods