A soil that is mineralogically an impure limestone. Such soils are also known as duricrust, kunkar, nari, kafkalla, Omdurman lime, croute, and race. Many soil profiles in semiarid climates (that is, those characterised by a rainfall of 4–20 in. or 10–50 cm per year) contain concentrations of calcium carbonate (CaCO₃). This calcium carbonate is not an original feature of the soils but has been added to the C horizon during soil formation either by direct precipitation in soil pores or by replacement of preexisting material. Fossil analogues of caliche, which are widely reported in ancient sedimentary sequences, are referred to as calcrete or cornstone.