calcifying

Calcifying refers to the process of calcification, where calcium salts accumulate in tissues or organisms, often forming hard structures. The most common salts are calcium phosphate (hydroxyapatite) and calcium carbonate. It occurs in biology, medicine, and geology.

Biological calcification, or biomineralization, includes the formation of bones and teeth in animals, and the skeletons and shells of many marine organisms. In animals, osteoblasts lay down hydroxyapatite in bone; odontoblasts produce dentin; enamel is mineralized. Some invertebrates deposit calcium carbonate to build shells and skeletons, for example mollusks and corals; coccolithophores produce calcareous plates.

In medicine and pathology, calcification may be physiological or pathological. Dystrophic calcification occurs in damaged or necrotic tissue with normal calcium levels; metastatic calcification results from elevated blood calcium or phosphate levels. Common sites include arteries, heart valves, kidney tubules, and soft tissues. Calcium phosphate deposition can be visible on radiographs and may impact organ function.

In geology and ecology, calcifying organisms contribute to carbonate sediments and limestone formation, shaping reef ecosystems; carbonate rocks such as chalk and limestone form from accumulated calcareous remains. These processes influence the structure of coastal environments and the global carbon cycle.