In the field, soil texture can be estimated by extracting a handful of sod and squeezing the damp soil into three basic shape; (1) cast, a lump formed by squeezing a simple in a clenched first; (2) thread, a pencil shape formed by rolling soil between the palms; and (3) ribbon, a flatfish formed by squeezing a small sample between the thumb and index finger, the behavioral characteristics of the soil when molded into each of these shapes, if they can be formed at all, provides the basic for a general texture classification. The behavior of the soil in the hand test is determined by the amount of clay in the sample. Clay particles are highly cohesive, and when dampened, behave as a plastic. Therefore the higher the clay content in a sample, the more refined and durable the shapes into which it can be molded.