The only notable difference between the two is symplesite's common blue color. Parasymplesite is isostructural with members of the Vivianite Group . While symplesite is not quite isostructural, it is closely related to minerals that would seem to make up their own meta group to the Vivianite Group. Such minerals as metakottigite and metavivianite are the triclinic dimorphs of the monoclinic minerals kottingite and vivianite . Maybe parasymplesite should be the triclinic dimorph instead of symplesite.
Color is blue, deep blue, greenish blue or green.
Luster is vitreous to pearly. Crystals are transparent to translucent. Crystal System is triclinic. Crystal Habits include spherical aggregates and crusty powders. Cleavage is perfect.