陕西略阳五花石的矿物学研究

Mineralogical Study of Wuhuaite from Lueyang County, Shanxi Province

陕西略阳白水江所产五花石是一种石雕原料,其矿物成分以高岭石为主,并含有少量或极少量的褐铁矿、赤铁矿、重晶石、明矾石、三水铝右、炭质等。本文提供了高岭石的湿化学分析、X射线粉晶衍射、差热分析、红外吸收光谱、电子显微镜分析等多种方法测试的数据,证明它是属于有序度高、结晶良好的高岭石,可与苏州高岭石相比。由于成矿地质环境的特殊性,该五花石属硬质粘土,无天然塑性,质地坚硬、细腻,雕刻性能良好,是粘土类矿物所组成的别具风格的天然工艺石雕原料。

Wuhuaite occurring at Baishuijiang, Lueyang County, Shanxi Province, is akind of matetial for stone carving. It has kaolinite as the major mineral compo-sition, and also contains small or negligible amounts of limonite, hematite,barite, alunite, gibbsite and carbon materials. Chemical composition of kaoliniteis SiO_2, 45.54%, TiO_2 0.05%, Al_2O_3 39.21%, Fe_2O_3 0.21%, FeO 0.068%, MnO0.016%, CaO 0.22%, MgO 1.33%, H_2O^+ 13.72%, K_2O 0.06% and Na_2O 0.036%,totally 100.46%. Its crystallochemical formula is (Al_(3.985)Fe_(3+0.013))_(3.998)Si_(3.923)O_(10)(OH))8.Unit cell parameters: a_o= 5.142±0.006; b_o= 8.947±0.011; c_o= 7.363±0.009 A;α= 91°42'±11'; β= 104°22'±11';γ=89°37'±11'; V=328.007 ± 0.503 A^3. Thispaper also provides data of kaolinite obtained by various means such as X--raypowder diffraction, differential thermal analysis, infrared spectroscopic analysisand electron microprobe analysis, which Prove it to be a kind of kaolinite withhigh order of degree and good crystallinity. Formed in a specific geologicalenvironment, wuhuaite belongs to hard clay without natural plasticity and hashard, fine and smooth quality suitable for carving.Composed of clay minerals,it is a natural material for stone carving.