HIGH-RESOLUTION TEM IMAGING OF EXTREME FAULTING IN NATURAL ZEOLITE TSCHERNICHITE

High-resolution TEM images and electron diffraction patterns confirm t he natural mineral tschernichite to be the topological equivalent to t he important synthetic zeolite beta. Though crystallization under natu ral conditions is expected to lead to the formation of regular stackin g of the layers, this natural zeolite mineral exhibits extremely high stacking fault frequencies. Such fault frequency is surprisingly equiv alent to that of its synthetic counterpart. Compositional zoning, whic h could have occurred during hydrothermal genesis, was not observed. T he crystals of natural tschernichite are embedded in a thin layer of c ation deficient amorphous silica-alumina or clay which is proposed as the source of these elements for this zeolite's nucleation and subsequ ent crystallization.