Editing Sediment (section)

====Form====
{{See also|Sphericity}}
Form (also called ''sphericity'') is determined by measuring the size of the particle on its major axes. [[William C. Krumbein]] proposed formulas for converting these numbers to a single measure of form,<ref>{{cite journal |last1=Krumbein |first1=William C. |title=Measurement and Geological Significance of Shape and Roundness of Sedimentary Particles |journal=SEPM Journal of Sedimentary Research |date=1941 |volume=11 |pages=64–72 |doi=10.1306/D42690F3-2B26-11D7-8648000102C1865D}}</ref> such as

:<math>\psi_l = \sqrt[3]{\frac{D_S D_I}{D_L^2}}</math>

where <math>D_L</math>, <math>D_I</math>, and <math>D_S</math> are the long, intermediate, and short axis lengths of the particle.{{sfn|Boggs|2006|p=582}} The form <math>\psi_l</math> varies from 1 for a perfectly spherical particle to very small values for a platelike or rodlike particle.

An alternate measure was proposed by Sneed and Folk:<ref>{{cite journal |last1=Sneed |first1=Edmund D. |last2=Folk |first2=Robert L. |title=Pebbles in the Lower Colorado River, Texas a Study in Particle Morphogenesis |journal=The Journal of Geology |date=March 1958 |volume=66 |issue=2 |pages=114–150 |doi=10.1086/626490|bibcode=1958JG.....66..114S |s2cid=129658242 }}</ref>

:<math>\psi_p = \sqrt[3]{\frac{D_S^2}{D_L D_I}}</math>

which, again, varies from 0 to 1 with increasing sphericity.