NationMaster - Encyclopedia: Krumbein scale

Grain size refers to the physical dimensions of particles of rock or other solid. This is different from the crystallite size, which is the size of a single crystal inside the solid (a grain can be made of several single crystals). Sedimentary, volcanic, plutonic, metamorphic rock types of North America. ... A solid is a state of matter, characterized by a definite volume and a definite shape (i. ... A crystallite is a domain of solid-state matter that has the same structure as a single crystal. ... Quartz crystal A crystal is a solid in which the constituent atoms, molecules, or ions are packed in a regularly ordered, repeating pattern extending in all three spatial dimensions. ...

Grain sizes can range from very small colloidal particles, through clay, silt, sand, and gravel, to boulders. A colloid or colloidal dispersion, is a form of matter intermediate between a true solution and a mixture (suspension). ... Clay is a generic term for an aggregate of hydrous silicate particles less than 4 μm (micrometres) in diameter. ... Silt refers to soil or rock particles of a certain very small size range (see grain size). ... Patterns in the sand Sand is an example of a class of materials called granular matter. ... Gravel Gravel is rock that is of a certain size range. ... Categories: Stub ...

Size ranges define limits of classes that are given names in the Wentworth scale used in the United States. The Krumbein phi (φ) scale, a modification of the Wentworth scale created by W. C. Krumbein, is a logarithmic scale computed by the equation: Value A logarithmic scale is a scale of measurement that gives the logarithm of a physical quantity instead of the quantity itself. ...

φ = - log 2 (grain size in mm)

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	½–1 mm	0.020–0.039 in	Coarse sand
2 to 1	¼–½ 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	3.90625–62.5 µm	0.00015–0.0025 in	Silt
> 8	< 3.90625 µm	< 0.00015 in	Clay

<10	< 1 µm	< 0.000039 in	Colloid

In some schemes "gravel" is anything larger than sand (>2.0 mm), and includes "granule", "pebble", "cobble", and "boulder" in the above table. In this scheme, "pebble" covers the size range 4 to 64 mm (−2 to −6 φ). Categories: Stub ... Cobble is a geologic term for a rock or rock fragment with a grain size with dimensions between 64–256 mm (2. ... Gravel Gravel is rock that is of a certain size range. ... Categories: Geology stubs | Sedimentology | Materials ... Gravel Gravel is rock that is of a certain size range. ... Categories: Geology stubs | Sedimentology | Materials ... Gravel Gravel is rock that is of a certain size range. ... Categories: Geology stubs | Sedimentology | Materials ... Gravel Gravel is rock that is of a certain size range. ... Categories: Geology stubs | Sedimentology | Materials ... Gravel Gravel is rock that is of a certain size range. ... An assortment of grains The word grain has a great many meanings, most being descriptive of a small piece or particle. ... Patterns in the sand Sand is an example of a class of materials called granular matter. ... Patterns in the sand Sand is an example of a class of materials called granular matter. ... Patterns in the sand Sand is an example of a class of materials called granular matter. ... Patterns in the sand Sand is an example of a class of materials called granular matter. ... Patterns in the sand Sand is an example of a class of materials called granular matter. ... Silt refers to soil or rock particles of a certain very small size range (see grain size). ... Clay is a generic term for an aggregate of hydrous silicate particles less than 4 μm (micrometres) in diameter. ... A colloid or colloidal dispersion, is a form of matter intermediate between a true solution and a mixture (suspension). ...

Categories: Sedimentary rocks

Results from FactBites:

KGS--Bulletin 169--Krumbein (4511 words)
	Cyclothems also provide a natural hierarchy of scales of observation, ranging in vertical sequence from an individual cyclothem member to a multicyclical stratigraphic unit, and ranging in a lateral sense from a single outcrop to the total area of occurrence of a member, a cycle, or a group of cycles.
	The lateral scale, assumed horizontal, presents some difficulties in quantification, inasmuch as a study may be framed on a very local scale (such as adjacent outcrops along a valley wall), or on a regional scale that extends over the whole area of occurrence of the unit of interest.
	As expressed in Table 1, the horizontal scale may be thought of as the diameter of a circle that encloses an area of study.

Logarithmic scale - Wikipedia, the free encyclopedia (531 words)
	A logarithmic scale is a scale of measurement that uses the logarithm of a physical quantity instead of the quantity itself.
	Richter magnitude scale for strength of earthquakes and movement in the earth.
	A logarithmic scale is also a graphic scale on one or both sides of a graph where a number x is printed at a distance c·10^log(x) from the point marked with the number 1.

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