Apatite is a group of phosphate minerals, usually hydroxyapatite, fluorapatite and chlorapatite, with high concentrations of OH−, F− and Cl− ion, respectively, in the crystal. The formula of the admix
Apatite (purple), on siderite, from Portugal
Faceted blue apatite, Brazil
Apatite in photomicrographs of a thin section from the Siilinjärvi apatite mine. In cross-polarized light on left, plane-polarized light on right.
An apatite mine in Siilinjärvi, Finland
Hydroxyapatite is a naturally occurring mineral form of apatite with the formula Ca53, often written Ca1062 to denote that the crystal unit cell comprises two entities. It is the hydroxyl endmember of
Apatite
…Apatite is a group of phosphate minerals, usually hydroxyapatite, fluorapatite and chlorapatite, with high concentrations of OH−, F− and Cl− ion, respectively, in the crystal. The formula of the admixture of the three…
Hydroxyapatite crystals on matrix
Needle-like hydroxyapatite crystals on stainless steel. Scanning electron microscope picture from University of Tartu.