Light and X-Ray Scattering at the Incommensurate Transition of Quartz

Abstract

The opalescence observed at the α-inc transitions of quartz is an example of the light scattering produced by complex microstructures occurring at the phase interface of first order phase transitions. Recently three models, related to the existence of the incommensurate phase of quartz, have been proposed to explain this light scattering. A new investigation of the origin of the quartz opalescence combining optical and high energy x-ray diffraction measurements has been performed. A diffuse x-ray streak observed between α and inc phases is probably associated to the structure of elongated triangles observed by electron microscopy.