Sepiolite deposits have been recently discovered in northeastern Iran. However, there is still little information about its physicochemical and mineralogical characteristics. Therefore, the collapse of the sepiolite (with sizes of < 63 μm) structure induced by temperature elevation in an electric furnace at 350, 550, and 850 °C for 4 hours was studied using X-ray diffraction (XRD) in combinatio...

Abstract The presence of amorphous silicate particles in interstellar and circumstellar space has been suggested based on the observation 9.7 18 μ m emission bands. We have successfully synthesized samples an enstatite forsterite composition by mechanical milling mixed powder consisting SiO 2 –MgO –Mg(OH) reagent-grade under different rotation frequencies times. These two types starting materia...

The prograde, high pressure, transition from antigorite serpentinite to enstatite-olivine rock occurs along a tectonically undisturbed pro®le at Cerro del Almirez, SE Spain. The reactant assemblage is antigorite + olivine with tremolite rimming precursor diopside. The product assemblage of tremolite + chlorite + enstatite + olivine has a spinifex-like texture with arborescent or radiating olivi...

A multianvil apparatus ha been used to determine th pressure-temperature mel ing curve of forsterite from 9.7 to 16.5 GPa. At 10.1 GPa a singular point occurs that marks the change from congruent melting at lower pressures to incongruent melting (forsterite periclase + liquid) at higher pressures. The melting curve also passes through two invariant points. At one (15.6 GPa, 2310øC), the phases ...