Sand-grain frosting and quartz overgrowth examined by scanning electron microscopy; the Navajo Sandstone (Jurassic (?)), Utah Available to Purchase

Under the SEM the frosted surfaces of quartz sand grains from middle and upper parts of the Navajo Sandstone are covered by small, raised platforms and, from place to place, larger pressure solution pits. Sand grains from the lower part of the sandstone display several stages in epitaxial overgrowth resulting in rhombohedrally and bipyramidally enclosed sand grains. The frosted surfaces as well as the epitaxial overgrowths are of diagenetic origin. The distribution of quartz cement appears to be related to the geomorphic expression and permeability of the Navajo Sandstone.