Parasymplesite is a rare iron arsenate mineral that can make nice micromounted specimens. It can form spherical aggregates of acicular crystals with a green color. It is dimorphous with the mineral symplesite, hence its name. Both minerals have the same exact chemistry, but they have different structures resulting in different symmetries. Parasymplesite is monoclinic while symplesite is triclinic.
Parasymplesite is also in a solid solution series with the mineral kottigite. A solid solution series exists when two or more elements can fill the same position within the structure of two or more minerals. In this case, iron and zinc can occupy the same position in the kottigite/parasymplesite structure. Kottigite is the zinc rich member of the series and parasymplesite is the iron rich member. Parasymplesite and kottigite are isostructural (meaning same structure) with all members of the Vivianite Group of minerals. However, not all of them share elements within their structures.