Table 7.7.

Grain size terminologies

Sedimentological terms (e.g. Stow 2006)BS5930 terms used in engineering practice
BoulderBoulder
256200
GravelCobbleCobble
6463
PebbleCoarseGravel
20
Medium
46.3
GranuleFine
22
SandVery coarseCoarseSand
1
Coarse
0.50.63
MediumMedium
0.250.2
FineFine
0.125
Very fine
0.0630.063
SiltCoarseCoarseSilt
0.032
Medium
0.0160.02
FineMedium
0.008
Very fine0.0063
0.004Fine
ClayCoarse
0.0020.002Clay
Medium
0.001
Fine
0.0005
Very fine
0.00025
Colloid
  • All dimensions in mm.