Non-Apatitic Phosphate Minerals

Apart from those in the Apatite group, the best-known phosphate minerals inclnde Autunite, Crandallite, Lazulite, Millisite, Monazite, Torbernite, Turquoise, Vivianite, Wavellite andXenotime. Locations of the different minerals in this category, within the United Kingdom, have been listed, but most of these are present only in collectors amounts [la].  

Some phosphate minerals have closely related internal structures and these can be placed in isostructural gronps. Members of such groups can sometimes form mutual solid solutions over a range of composition. In addition to the Apatite group, which includes a large number of minerals and synthetic prodncts (Chapter 5.3), there are, for example, those in Table 2.7. 

Isostructural arsenate analogues of many phosphate minerals are known, and in some cases vanadates also. Some orthophosphates are capable of forming complete ranges of solid solutions with the corresponding orthoarsenates  

Phosphate minerals, like silicate minerals, are found with a great variety of cations. Unlike the latter group, which contains numerous types of condensed silicate anions, almost all phosphate minerals are orthophosphates which contain the PO anion. 

Non-phosphorus anions such as CP, OH, F, Cl, SOI , SiO, AsO, and so forth may also be present in these stochiometrically (or as occluded material) (Chapter 5.3). 

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