Phosphates - Group of minerals that are compounds of one or more metallic elements associated with the phosphate radical (PO₄). The phosphates are classified together with the arsenates and vanadates.
Most phosphates are heavy, and none are hard. They are usually brittle and occur in small crystals or compact aggregates.
(In this guide, "true phosphates" refers only to minerals with the phosphate radical, excluding the arsenates and vanadates which contain the arsenate and vanadate radicals.)