Mineralogical Characteristics of a Kind of Red Stone Needle

This paper investigates the mineralogical characteristics of a kind of red stone needle by using X-ray diffraction(XRD), scanning electron microscopy(SEM), thermogravimetric analysis(TG-DTG)and laser induced breakdown spectroscopy(LIBS).The XRD result shows that the red stone needle is mainly composed of dolomite, containing minor quartz and calcite, and trace mica, orthoclase and hematite.SEM result indicates that mineral aggregates dominate in the red stone needle with their grain size ranging from 1μm to 5μm and different degrees of smoothness on their surfaces.A single weightlessness peak occurs between 650℃ and 850℃, which should be attributed to the thermal decomposition of dolomite and the occurrence of isomorphism or foreign minerals leading to the simultaneous accomplishment of the two-stage decompositions.The coloration might result from the average distribution of hematite and orthoclase in the red stone needle.