Apatite Wikipedia
Apatite is a group of phosphate minerals usually hydroxyapatite fluorapatite and chlorapatite with high concentrations of OH − F − and Cl − ions respectively in the formula of the admixture of the three most common endmembers is written as Ca 10 PO 4 6 OH F Cl 2 and the crystal unit cell formulae of the individual minerals are written as Ca 10 PO 4 6 OH 2 Ca
