apatyt

Apatyt, known in English as apatite, is a group of phosphate minerals with the general formula Ca5(PO4)3(X), where X represents F, Cl, or OH. It is the most common phosphate mineral and the principal source of phosphorus for fertilizers. The minerals crystallize in the hexagonal system and commonly occur as prismatic crystals or massive aggregates. End-members include fluorapatite (Ca5(PO4)3F), chlorapatite (Ca5(PO4)3Cl), and hydroxyapatite (Ca5(PO4)3(OH)), with various solid solutions between them. Colors range from colorless to green, blue, brown, or yellow; transparency ranges from transparent to opaque; luster is vitreous to resinous.

Occurrence: Apatyt occurs in igneous and metamorphic rocks, including granites and alkaline rocks, and is common in sedimentary phosphorite deposits. It also occurs in carbonate-bearing rocks and as vein fillings.

Economy and biology: Apatyt is the primary source of phosphorus used in agricultural fertilizers and in the production of phosphoric acid, phosphate chemicals, and ceramics. In biology, a form of hydroxyapatite is the main mineral component of bone and tooth enamel in vertebrates, giving bones and teeth their rigidity.

Significance: Beyond its industrial role, apatyt is useful for geological dating and tracing phosphate cycles in the environment. The mineral often forms through a variety of processes, including igneous differentiation, sedimentary phosphorite formation, and biosilicification in some environments.