Pocket-sized folder enables the field geologist to quickly and accurately identify grain size and shape, grain sorting, roundness, and sphericity of a sample. Consists of sphericity/roundness measuring chart; printed examples of well-sorted and poorly-sorted grain samples in fine, medium, and coarse ranges; four actual grain samples illustrating angular, subangular, subrounded, and rounded shapes; six grain size samples: silt, very fine sand, fine sand, medium sand, coarse sand, and very coarse sand. Measurement limits for granules, pebbles, cobbles, and boulders indicated.