Ferric ferrocyanide, also known as Prussian blue, is not a mineral. It is a synthetic inorganic compound with the formula Fe7(CN)18•xH2O. It is a dark blue pigment that is used in paints, inks, and dyes.

Ammonium is not a mineral either. It is a polyatomic cation with the formula NH4+. It is found in many minerals, such as ammonium chloride, ammonium sulfate, and ammonium nitrate. However, ammonium itself is not a mineral.