loose and powdery deposit or a massive crystalline structure. The profile of a gypcrust outcrop can have three layers. The bottom layer is the sand rose horizon at the water table where gypsum develops as aggregates of crystals. The middle layer is composed of massive gypcrete cemented sand, which forms above the water table during evaporation from the capillary fringe; newly formed gypcrete will be hard, and will soften with age. The uppermost layer is usually rich in gypsified roots and has a banded or nodular structure. Uses Gypcrete has been used successfully for road construction in the Sahara. Well-cemented gypcrusts may also provide adequate bearing capacity for structures, however it must be ensured that the underlying uncemented material is not overloaded to avoid collapse. See also References Soil