Encyclopedia > Apatite

  Article Content

Apatite

Apatite is a mineral, or rather an admixture of three minerals: hydroxyapatite, fluorapatite, and chlorapatite, named for high concentrations of OH-, F-, or Cl- ions, respectively, in the crystal lattice. The formula of this admixture is Ca5(PO4)3(OH, F, Cl).

Mohs hardness is 5. Refractive index is 1.632-1.646. Specific gravity is 3.17-3.23. Birefringence is .002-.004. Crystal structure is hexagonal.

Apatite is one of very few minerals which are produced and used by biological systems. Hydroxyapatite is the major component of tooth enamel[?], and a large component of bone material. Fluorapatite is slightly stronger than hydroxyapatite; thus, fluoridated water[?], which will allow exchange in the teeth of hydroxyl ions for fluoride ions, slightly strengthens the teeth.

Fission tracks[?] in apatite are commonly used to estimate the thermal history of sediments in sedimentary basins.

See also: list of minerals, thermal history modelling.



All Wikipedia text is available under the terms of the GNU Free Documentation License

 
  Search Encyclopedia

Search over one million articles, find something about almost anything!
 
 
  
  Featured Article
Springs, New York

... female householder with no husband present, and 34.9% are non-families. 26.1% of all households are made up of individuals and 9.6% have someone living alone who is 65 ...

 
 
 
This page was created in 27.2 ms