1. Structureless - no observable aggregation or no definite orderly arrangement around natural lines of weakness. |
A. Single grain - loose, incoherent mass of individual particles as in sands. |
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B. Amorphous (massive) - a coherent mass showing no evidence of any distinct arrangement of soil particles. |
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2. Blocklike-soil particles arranged around a point and bounded by flat or rounded surfaces. |
A. Blocky (angular blocky)- rectangular and flattened, vertices sharply angular |
Fine blocky, |
<10 |
Medium blocky, |
10-20 |
Coarse blocky, |
20-50 |
Very coarse blocky |
>50 |
B. Subangular blocky-faces subrectangular, vertices mostly oblique, or subrounded. |
Fine subangular blocky, |
<10 |
Medium subangular blocky, |
10-20 |
Coarse subangular blocky, |
20-50 |
Very coarse subangular blocky |
>50 |
C. Granular-spheroidal-characterized by rounded vertices. |
Fine granular, |
<2 |
Medium granular, |
2-5 |
Coarse granular, |
5-10 |
3. Platelike-soil particles arranged around a horizontal plane and generally bounded by relatively flat horizontal surfaces. |
A. Platy-horizontal planes more or less developed. |
Fine platy, |
<2 |
Medium platy, |
2-5 |
Coarse platy, |
>5 |
4. Prismlike-soil particles arranged around a vertical axis and bounded by relatively flat vertical surfaces. |
A. Prismatic-vertical faces Fine well defined and edges sharp. |
Fine prismatic, |
<20 |
Medium prismatic, |
20-50 |
Coarse prismatic, |
50-100 |
Very Coarse prismatic, |
>100 |
B. Columnar-vertical edges near top of columns not sharp. (Columns may be flat-topped round-topped, or irregular). |
Fine columnar, |
<20 |
Medium columnar, |
20-50 |
Coarse columnar, |
50-100 |
Very Coarse columnar, |
>100 |