Brick Building emulating design and plaster of karshif, in Siwa, Oasis, Egypt. Karshif (also spelled kershif or karsheef, etc.) is a mud-salt mix taken from natural salt flats, which is used as building material in Siwa's traditional material mud brick architecture. Construction regulations require new buildings, even if built with bricks to be covered with karshif plaster to mimic traditional buildings.