Phosphate occurrences in soils and pedosediments are relatively rare and most commonly associated with human activities. With the exception of vivianite they are poorly documented with regard to their micromorphological features. Numerous types of phosphates are found in archaeological sites where both human and animal inputs (e.g. bird and bat guano) are responsible for significant diagenesis, involving the transformation and production of various phosphate minerals, such as Al and Ca-Al phosphates (crandallite, montgomeryite, variscite) and vivianite. In this chapter, we briefly summarize the occurrence and micromorphology of several of these minerals, which are particularly well preserved and documented from archaeological soils and deposits.