abstract:The ferrierite group of zeolite minerals (the FER structure) consists of three very similar species: ferrierite-Mg, ferrierite-Na, and ferrierite-K, based on the dominant cation in the A location. Ferrierites are orthorhombic minerals with highly variable cationic composition, (Na,K)2Mg(Si,Al)18O36(OH)·9H2O.