Fossilization

thumb|upright=1.25|petrified wood|Tree remains that have undergone petrifaction, as seen in [[Petrified Forest National Park]]

Permineralization is a process of fossilization of bones and tissues in which mineral deposits form internal casts of organisms. Carried by water, these minerals fill the spaces within organic tissue. Because of the nature of the casts, permineralization is particularly useful in studies of the internal structures of organisms, usually of plants.

thumb|right|A natural endocast of the brain of the Taung Child, a young [[Australopithecus africanus, with the facial portion of the skull attached]] An endocast is the internal cast of a hollow object, often referring to the cranial vault in the study of brain development in humans and other organisms. Endocasts can be artificially made for examining the properties of a hollow, inaccessible space, or they may occur naturally through fossilization.