Study On The Influencing Factors Of Transparence And Color Gensis Of Balin Stone

Balin stone, as one of“Four Famous Seal stones of China”，is becomingas uperior stone preferred by the sculptors and collectors. This paper,with yel-low Balin stone as the the object, has done some research on geological feat-ures of ore deposit、the influencing factors of transparency and color gensis ofBalin stone through using modern testing methods.Study on transparency of Balin stone indicates that average grain size、uni-formity of grain、crystallnite、water、inclusions and cracks are the factors thatcan affect the transparence of the Balin stone. The samples’ transparencies aredivied into three levels: good, medium and poor by transmittance text; Micro-morphology observation by SEM examination shows that the smaller the average sizes and the more homogeneous the size are, the better the transparence is;XRD shows that there exist the characteristic diffraction peaks of kaolinite and dickite；the HI index and the A1/A2index have been calculated to testify that the more transparent one has better degree of order or has a higher crystallinite; intensity(A2) of3620cm-1ascribing to inner layer OH vibration drop off asthe transparence raise,which speculation the content of inner layer OH influence the transparency of Balin stone. DTA curve shows that the dehydroxylationtemperature of transitional mineral of kaolinte and dickite is at about600℃，with the temperature droping off as the transparence go better, and there is an exothermic peak at970°C. TG curve shows that the worse transparent the stoneis, the more water lose; dark and opaque subordinate minerals are also influeneing factors of transparence.Balin Stone deposit attributes to low-temperature hydrothermal alteration type. Multi-periodic hydrothermal alter formed mineral, strengthening the forceamong layers, disordered mineral transformed into ordered one. Impurities arefiltered out by hydrothermal, the mineral becomes more and more transparent.Colouration mechanism is studied to explain that yellow Balin stone hasabundant limonites, which is the main influencing factor affected stone’color,and Fe3+can enter into crystal lattice to help for yellowness.