The different sizes depending upon the type of limestone, kind of kiln used, or treatment subsequent to calcining. The sizes commonly recognized are as follows: (1) large lump-- 8 in (203 mm) and smaller; (2) pebble or crushed--2-1/2 in (64 mm) and smaller; (3) ground, screened, or granular--1/4 in (6.4 mm) and smaller; and (4) pulverized-- substantially all passing a No. 20, 850 mu m, sieve.