THE MINERAL SYMPLESITE

• Chemistry: Fe3(AsO4)2 - 8H2O, Hydrated Iron Arsenate
• Class: Phosphates
• Subclass: Arsenates
• Uses: Only as mineral specimens.
• Specimens

Symplesite is a very rare iron arsenate mineral. It is dimorphous with the mineral parasymplesite. Both minerals have the same exact chemistry, but they have different structures resulting in different symmetries. Parasymplesite is monoclinic while symplesite is triclinic. 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.

PHYSICAL CHARACTERISTICS:

• Color is blue, deep blue, greenish blue or green.
• Luster is vitreous to pearly.
• Transparency: Crystals are transparent to translucent.
• Crystal System is triclinic.
• Crystal Habits include spherical aggregates and crusty powders.
• Cleavage is perfect.
• Fracture is uneven.
• Hardness is 2.5
• Specific Gravity is approximately 3.0 - 3.1 (average for translucent minerals).
• Streak is white.
• Associated Minerals are kottigite, pyrite, lollingite and parasymplesite
• Notable Occurrences include Alsace, France; Custer County, South Dakota, USA; Lobenstein, Germany; Italy; Tasmania, Australia and Japan.
• Best Field Indicators are color, crystal habit, cleavage, softness and associations.