Average size of a grain of sand

Q: How big is a typical grain of sand?

Any particles from 0.06mm to 2.0mm are considered to be sand. Particles larger than size 5 are considered gravel.

Q: What is the average particle size of sand?

Sand ranges from 0.05 to 2.0 mm. Particles larger than 2.0 mm are called gravel or stones. Most soils contain a mixture of sand, silt and clay in different proportions.

Q: What is the volume of 1 grain of sand?

Assuming a grain of sand is roughly spherical, the average volume of a grain is 4/3 x pi x r3=0.00947mm3, where r is the radius.

Q: How big is a grain of sand in micrometers?

Geologist Chester K. Wentworth defined sand in a publication in 1922, along with gravel, silt, and mud. Sand-sized particles range in size from 63 microns to 2 millimeters. Gravel is anything larger than that; silt and mud are finer.

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Krumbein phi scale[edit]
International scale[edit]
Sorting[edit]
See also[edit]
References[edit]
External links[edit]
How big is a typical grain of sand?
What is the average particle size of sand?
What is the volume of 1 grain of sand?
How big is a grain of sand in micrometers?

Bibliographic Entry	Result (w/surrounding text)	Standardized Result
Earth Science: A Study of a Changing Planet. Newton, MA: CEBCO, 1990.	"as shown in table 14-1, particles that range from about 2 mm down to about 0.05 mm in diameter are called sand"	0.05–2 mm
"Soil." Microsoft Encarta. CD-ROM. Redmond, WA: Microsoft, 1996.	"Particles of sand range in size from 2 to 0.05 mm in diameter; those of silt from 0.05 to 0.002 mm and those of clay smaller than 0.002 mm."	0.05–2 mm
Glossary. Erosion and Sediment Control Management System. Lake Macquarie, Australia: 9 September 1999.	"Sand consists of particles consisting largely of quartz grains between 0.02 mm and 2.00 mm in diameter. Fine sand is defined as particles between 0.02 mm and 0.2 mm and course [sic] sand as those between 0.2 mm and 2.0 mm."	0.02–2 mm
Bloom, Arthur. The Surface of the Earth. Englewood Cliffs, NJ: Prentice Hall, 1969.	"for sediment grains coarser than fine sand (average diameter 0.2 mm), the current velocity…."	0.2 mm (average)
"Relationship of Transported Particle Size to Water Velocity." 1994 Earth Science Reference Tables. Albany, NY: University of the State of New York, 1994.	[table]	0.06–2 mm

Soil is made up of a mixture of mineral and organic particles produced by the interaction of wind, water, and organic decay. The physical structure of soil at any location is determined by many factors such as the kind of geologic material from which it originates, vegetation, the length of time that the soil has been weathered, topography, and artificial changes caused by human activities. However, the general texture of a soil depends on the proportions of particles of various sizes of which it is composed. Soil particles are divided into sand, silt, clay and colloids.

Sand is composed of loose, finely grained minerals that are the product of chemical and mechanical decomposition of rocks over long periods of time. These minerals include quartz (the most common mineral) with traces of mica, feldspar, and magnetite. Sand consists mostly of quartz because other common minerals weather away to sizes smaller than sand, and quartz does not

Sand is very important in the making of glass, certain types of moldings and sandblasting. Since sand is very abundant on the shore lines of lakes, seas and oceans, it serves a recreational purpose by providing the material to build sand castles, and to bury your friend, family member, or dog on a boring day.

Ilana Price -- 2000

External links to this page:

A Simple Grain of Sand [pdf], Roger van Cleef, Memphis Archaeological and Geological Society Rockhound News, Vol. 48 No. 11 (2002)
How to (Maybe) Find Your Own Little Amazing Meteorite. SciShow Space. Youtube (2020).

Not to be confused with crystallite size, which is referred to as "grain sizes" by metallurgists.

Granulometry

Basic concepts
Particle size · Grain size Size distribution · Morphology
Methods and techniques
Mesh scale · Optical granulometry Sieve analysis · Soil gradation
Related concepts
Granulation · Granular material Mineral dust · Pattern recognition Dynamic light scattering
v t e

Wentworth grain size chart from United States Geological Survey Open-File Report 2006-1195: Note size typos; 33.1mm is 38.1 & .545mm is .594

Grain size (or particle size) is the diameter of individual grains of sediment, or the lithified particles in clastic rocks. The term may also be applied to other granular materials. This is different from the crystallite size, which refers to the size of a single crystal inside a particle or grain. A single grain can be composed of several crystals. Granular material can range from very small colloidal particles, through clay, silt, sand, gravel, and cobbles, to boulders.

Krumbein phi scale[edit]

Size ranges define limits of classes that are given names in the Wentworth scale (or Udden–Wentworth scale) used in the United States. The Krumbein phi (φ) scale, a modification of the Wentworth scale created by W. C. Krumbein[1] in 1934, is a logarithmic scale computed by the equation

where

is the Krumbein phi scale, is the diameter of the particle or grain in millimeters (Krumbein and Monk's equation)[2] and is a reference diameter, equal to 1 mm (to make the equation dimensionally consistent).

This equation can be rearranged to find diameter using φ:

φ scale	Size range (metric)	Size range (approx. inches)	Aggregate name (Wentworth class)	Other names
<−8	>256 mm	>10.1 in	Boulder
−6 to −8	64–256 mm	2.5–10.1 in	Cobble
−5 to −6	32–64 mm	1.26–2.5 in	Very coarse gravel	Pebble
−4 to −5	16–32 mm	0.63–1.26 in	Coarse gravel	Pebble
−3 to −4	8–16 mm	0.31–0.63 in	Medium gravel	Pebble
−2 to −3	4–8 mm	0.157–0.31 in	Fine gravel	Pebble
−1 to −2	2–4 mm	0.079–0.157 in	Very fine gravel	Granule
0 to −1	1–2 mm	0.039–0.079 in	Very coarse sand
1 to 0	0.5–1 mm	0.020–0.039 in	Coarse sand
2 to 1	0.25–0.5 mm	0.010–0.020 in	Medium sand
3 to 2	125–250 μm	0.0049–0.010 in	Fine sand
4 to 3	62.5–125 μm	0.0025–0.0049 in	Very fine sand
8 to 4	3.9–62.5 μm	0.00015–0.0025 in	Silt	Mud
10 to 8	0.98–3.9 μm	3.8×10−5–0.00015 in	Clay	Mud
20 to 10	0.95–977 nm	3.8×10−8–3.8×10−5 in	Colloid	Mud

In some schemes, gravel is anything larger than sand (comprising granule, pebble, cobble, and boulder in the table above).

International scale[edit]

ISO 14688-1:2002, establishes the basic principles for the identification and classification of soils on the basis of those material and mass characteristics most commonly used for soils for engineering purposes. ISO 14688-1 is applicable to natural soils in situ, similar man-made materials in situ and soils redeposited by people.[3]

ISO 14688-1:2017

Name	Size range (mm)	Size range (approx. in)
Very coarse soil	Large boulder	lBo	>630	>24.8031
Boulder	Bo	200–630	7.8740–24.803
Cobble	Co	63–200	2.4803–7.8740
Coarse soil	Gravel	Coarse gravel	cGr	20–63	0.78740–2.4803
Medium gravel	mGr	6.3–20	0.24803–0.78740
Fine gravel	fGr	2.0–6.3	0.078740–0.24803
Sand	Coarse sand	cSa	0.63–2.0	0.024803–0.078740
Medium sand	mSa	0.2–0.63	0.0078740–0.024803
Fine sand	fSa	0.063–0.2	0.0024803–0.0078740
Fine soil	Silt	Coarse silt	cSi	0.02–0.063	0.00078740–0.0024803
Medium silt	mSi	0.0063–0.02	0.00024803–0.00078740
Fine silt	fSi	0.002–0.0063	0.000078740–0.00024803
Clay	Cl	≤0.002	≤0.000078740

Sorting[edit]

An accumulation of sediment can also be characterized by the grain size distribution. A sediment deposit can undergo sorting when a particle size range is removed by an agency such as a river or the wind. The sorting can be quantified using the Inclusive Graphic Standard Deviation:[4]

where

is the Inclusive Graphic Standard Deviation in phi units is the 84th percentile of the grain size distribution in phi units, etc.

The result of this can be described using the following terms:

Diameter (phi units)	Description
< 0.35	very well sorted
0.35 < < 0.50	well sorted
0.50 < < 1.00	moderately sorted
1.00 < < 2.00	poorly sorted
2.00 < < 4.00	very poorly sorted
4.00 <	extremely poorly sorted

References[edit]

^ Krumbein, W. C. (1934). "Size frequency distributions of sediments". Journal of Sedimentary Petrology. 2 (4). doi:10.1306/D4268EB9-2B26-11D7-8648000102C1865D.
^ PetroWiki: Estimating permeability based on grain size
^ "ISO 14688-1:2002 – Geotechnical investigation and testing – Identification and classification of soil – Part 1: Identification and description". International Organization for Standardization (ISO).
^ Folk, Robert L.; Ward, William C. (1957). "Brazos River bar: a study in the significance of grain-size parameters" (PDF). Journal of Sedimentary Petrology. 27 (1): 3–26. Bibcode:1957JSedR..27....3F. doi:10.1306/74d70646-2b21-11d7-8648000102c1865d. Archived from the original (PDF) on 12 May 2014. Retrieved 11 May 2014.

External links[edit]

R D Dean & R A Dalrymple, Coastal Processes with Engineering Applications (Cambridge University Press, 2002)
W C Krumbein & L L Sloss, Stratigraphy and Sedimentation, 2nd edition (Freeman, San Francisco, 1963).
Udden, J. A. (1914). "Mechanical composition of clastic sediments". Geological Society of America Bulletin. 25 (1): 655–744. Bibcode:1914GSAB...25..655U. doi:10.1130/GSAB-25-655.
Wentworth, C. K. (1922). "A Scale of Grade and Class Terms for Clastic Sediments". The Journal of Geology. 30 (5): 377–392. Bibcode:1922JG.....30..377W. doi:10.1086/622910. JSTOR 30063207. S2CID 128682870.

How big is a typical grain of sand?

Any particles from 0.06mm to 2.0mm are considered to be sand. Particles larger than size 5 are considered gravel.

What is the average particle size of sand?

Sand ranges from 0.05 to 2.0 mm. Particles larger than 2.0 mm are called gravel or stones. Most soils contain a mixture of sand, silt and clay in different proportions.

What is the volume of 1 grain of sand?

Assuming a grain of sand is roughly spherical, the average volume of a grain is 4/3 x pi x r³=0.00947mm³, where r is the radius.

How big is a grain of sand in micrometers?

Geologist Chester K. Wentworth defined "sand" in a publication in 1922, along with "gravel," "silt," and "mud." Sand-sized particles range in size from 63 microns to 2 millimeters. Gravel is anything larger than that; silt and mud are finer.