Study on Gemmological and Mineralogical Characteristics of “Lvlongjing”

Lvlongjing is a kind of chlorite jade from Russia,and its mineral component is widely regarded as clinochlore——a subspecies of chlorite.The "Lvlongjing" samples for the study have the unique dark green to celadon colour,lepidoblastic and foliaceous textures,density of 2.61~2.62 g/cm³,refractive index of about 1.57 and Mohs' hardness of about 2.5.The mineral component of the "Lvlongjing" sample is mainly composed of penninite——a subspecies of chlorite.The results of slice observation by microscope show that the penninite has thumb blue,brown and violet anomalous interference colour,parallel or proximal parallel extinction.The EMPA results indicate that the main chemical compositions of the "Lvlongjing" sampe are SiO₂ and MgO,followed by Al₂O₃ and FeO_T,and the chemical formula is calculated and projected to be in the area of penninite according to Fe²⁺/R²⁺ and atomicity of Si.The XRD result shows that there exist the characteristic diffraction peaks of penninite.The IR absorption peaks of "Lvlongjing" appear at 3 637,3 465,1 048,1 001,967 cm^-1 and 444 cm^-1 that accord with the IR characteristics of penninite.