Gemmological, Petrographic Characteristics and Petrogenesis of Quartz Jadeitite with Barite Inclusion

A kind of purple jadeitite is studied by gemmological and petrological methods. It was found that in system identification of the rock by polarizing microscope, the sample is albite quartz microcrystalline jadeitite, and the quartz contains columnar, slaty and granular barite inclusions. The purple parts of the sample are jadeite and the white parts are quartzs. Raman spectrum confirms that the inclusions in quartz are barite, which supports the inclusion identification results of polarizing microscope. UV-Vis spectrum and the qualitative analysis results of energy dispersive X-ray fluorescence spectrum show that the strongest absorption band between 500-600 nm, with about 580 nm as the center is caused by Mn, which causes the purple colour of the jadeitite. Based on the petrographic characteristics, it is considered that some jadeite reacted with quartz to form micrograined albite mixed in the jadeite aggregates with the slowly decrease of pressure after the jadeitite metamorphic crystallization, while the SiO₂ rich colloidal hydrothermal adsorbed with Ba²⁺ intruded along the fractures of jadeitite. The Ba²⁺ released in the SiO₂ colloidal flocculation stage and reacted with SO₄^2-to form tiny, idiomorphic barite, which were then included by crystallized quartzs, then a rare phenomenon that included in quartzs barite and distributed in jadeite as the form of flow structure in jadeitite.