The basic chemical unit of Phosphates Mineral Class is the tetrahedral groups AO4 with negative three charge. The A in the unit can be either Antimony, Phosphorus, Vanadium, or Arsenic. The combination of the basic chemical unit of Phosphates Class with metal ions is usually one to one ratio or more complex combination if combined with other ions such as the OH or hydroxide group, UO2 or uranyl group, a halogen or even water molecules. The typical Phosphate is usually found exhibiting vitreous to dull luster in reflected light of the polarizing microscope. It is also often found strongly colored and usually splendidly exhibited under petrographic polarizing microscopes. Phosphates are typically found having above average density. The average hardness is usually ranging from 4 to 7 when evaluated using the Mohs scale method. Typical Phosphates are usually found having low index of refraction when viewed under polarized light microscope. Unless of course if ions such as lead are present. All other properties of Phosphates are variable. This mineral class can provide several interesting and beautiful mineral specimens that are often exhibiting wonderful appearance when viewed under petrographic polarizing microscope. This mineral class comprises a very large number of minerals and only the Apatite Group is considered common. Apatite is an important biological mineral that can be found in teeth and also in bones of many animals.