| The cleavage planes of calcite and apophyllite in thermodynamic equilibrium with water were examined at atomic resolution using an atomic force microscope (AFM). The average two dimensional fast Fourier transform of the calcite images exhibits a rectangular unit cell 0.74(5)nm by 0.48(2)nm, and that of the apophyllite images exhibits a square unit cell 0.93(3)nm on edge.;Apophyllite images were consistent with the non-silicate layer of the structure, and this suggests counter-ion adsorption onto the silicate layer at the inner Helmholtz plane of the mineral-water interface. For periodic surfaces, averaging of images in Fourier space improves image quality without loss of information.;Digital Fe Kalpha, Mn Kalpha and Mg Kalpha X-ray maps of sections cut from a calcite crystal were collected using a Camebax s%50 automated electron microprobe. Features as small as ≈25 mum were resolved, as were changing growth forms, inter- and intra-sectoral zoning and dissolution events. The maps also allow reconstruction of qualitative changes in growth solution composition and the Miller indices of growth forms. |
