“Caliche” is a shallow layer of soil or sediment in which the particles have been cemented together by the precipitation of mineral matter in their interstitial spaces. The cement is usually calcium carbonate; however, cements of magnesium carbonate, gypsum, silica, iron oxide, and a combination of these materials are known.

Caliche is a common feature of arid or semiarid areas throughout the world. In the United States, caliche is a familiar deposit in many parts of the Southwest, especially in Arizona, California, Nevada, New Mexico, and Texas. There, caliche is associated with problems such as poor soil drainage, difficult soil conditions for plant growth, and excavation problems at construction sites. In some locations there are multiple ancient caliche layers in the subsurface.

The name “caliche” originates from a Spanish word for porous materials that have been cemented by calcium carbonate. The name is used to refer to a piece of the material or the layer from which it was broken, or the cement itself that binds the materials together. Caliche is known by many other names, the more common of which are calcrete, hardpan, duricrust, and calcic soil.