USGS - science for a changing world

Scientific Investigations Report 2008–5093

U.S. GEOLOGICAL SURVEY
Scientific Investigations Report 2008–5093

Back to Table of Contents

Table 3. Particle-size classification.

[Particle-size classification modified from Buffington and Montgomery (1999) and Folk (1980). Symbol: φ, phi scale where φ = -log2 (diameter in mm); Abbreviation: mm, millimeter]

Diameter of particle Classification
name
φ   mm
-8
256
Coarse cobble
-7
128
Fine cobble
-6
64
Very coarse gravel
-5
32
Coarse gravel
-4
16
Medium gravel
-3
8
Fine gravel
-2
4
Very fine gravel
-1
2
Very coarse sand
0
1
Coarse sand
1
.5
Medium sand
2
.25
Fine sand
3
.125
Very fine sand
4
.0625
Coarse silt
5
.0310
Medium silt
6
.0165
Fine silt
7
.0076

Back to Table of Contents

AccessibilityFOIAPrivacyPolicies and Notices

Take Pride in America logoUSA.gov logoU.S. Department of the Interior | U.S. Geological Survey
URL: http://pubs.usgs.gov/sir/2008/5093
Page Contact Information: Publications Team
Page Last Modified: Thursday, 10-Jan-2013 18:49:24 EST