Mineral Class 07: Phosphates, Arsenates, Vanadates

Dark green mimetite from (in 1876 closed mine) at Caldbeck Fells, Dry Gill, Cumberland, England, United Kingdom
Phosphate minerals are those minerals that contain the tetrahedrally coordinated phosphate (PO4) anion along with the freely substituting arsenate (AsO43-) and vanadate (VO43-). Chlorine (Cl-), fluorine (F-), and hydroxide (OH-) anions also fit into the crystal structure. The phosphate class of minerals is a large and diverse group, however, only a few species are relatively common.