Mineralogical properties of hydrothermal analcime in volcanic rocks of South Kahrizak

Analcime along with other zeolite group minerals such as: Tetranatrolite, Natrolite,Mesolite, Scolcite, Heulandite, Stilbites and, levyne occur as vein and cavity filling minerals in the intermediate to basic volcanic rocks in South Kahrizak. Scanning Electron Microscopy(SEM) of microcrystaline analcime reveal pseudo-cubic prismatic faces of [211] containinglaminations perpendicular to the elongation of the crystals. These laminations are due to crystal growth mechanism and are characteristics of hydrothermally formed analcime (H-type). X-ray diffraction study has revealed a pseudocubic symmetry for analcime with unit-cell parameters of: a = 13.6974(51) Å, b = 13.6874(124) Å, C = 13.6637(311) Å, V = 2561.695 Å3. Raman spectrum of the sample shows vibrational mode frequency for H2O molecules in analcime at about 3500 cm-1.