A term usually applied to material in suspension in water or recently deposited from suspension. The word sediments is used to describe different kinds of geologic deposits:

  • Sediment Type Size in inches size in millimeters
  • Boulder greater than 10.8 greater than 256
  • Cobble 2.52 – 10.8 64 – 256
  • Very Coarse Gravel 1.26 – 2.52 32 – 64
  • Coarse Gravel 0.63 – 1.26 16 – 32
  • Medium Gravel 0.31 – 0.63 8 – 16
  • Fine Gravel 0.16 – 0.31 4 – 8
  • Very Fine Gravel 0.08 – 0,16 2 – 4
  • Very Coarse Sand 0.04 – 0.08 1 – 2
  • Coarse Sand 0.02 – 0.04 0.5 – 1
  • Medium Sand 0.01 – 0.02 0.25 – 0.5
  • Fine Sand 0.005 – 0.01 0.125 – 0.25
  • Very Fine Sand 0.002 – 0.005 0.063 – 0.125
  • Silt 0.0002 – 0.002 0.004 – 0.063
  • Clay Less than0.0002 Less than 0.004