Grain Numbers
Grain numbers define the size of the grain. The number corresponds to the number of meshes per linear inch in the grading sieve. Common numbers are, from coarse to fine: 10, 12, 14, 16, 18, 20, 24, 30, 36, 40, 46, 54, 60, 70, 80, 90, 100, 120, 150, 180, and 200. Grains finer than 200 are known as "flour" and are designated by the letters: CF, F, FF, FFF, FFFF, and PCF or SF (coarse to fine). Note that the grades for flour are not standardized, so the same grade grains from different sources may differ in size slightly.
Read more about this topic: Emery (mineral)
Famous quotes containing the words grain and/or numbers:
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In the unloading. Silas does that well.
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—Robert Frost (1874–1963)