Ghirbal

A coarse hand sieve used to grade the soil for finishing plasters and adobe blocks. Pisé wall mixes typically include the full graded soil and a proportion of stone or gravel, but adobe and the upper finishing coats require a finer, more uniform fraction; the ghirbal removes the coarsest stones and roots before the mix is wetted. Grain size is one of the principal regulators of plaster quality; a maalem's choice of mesh and the number of sieving passes is a craft judgement transmitted through apprenticeship.