Mineralogical Characteristics Of Brucite From Fengcheng,Liaoning Province

The mineral composition of brucite is magnesium hydroxide,which is the highest content of magnesium found in nature so far.The experimental samples are from Xujiatai,Fengcheng City,Liaoning Province.In this paper,the Gemological characteristics,mineral composition,chemical composition,structural structure,color and their influencing factors of brucite block samples produced in this area were studied by hand specimen observation,polarizing microscopy,scanning electron microscopy,X-ray powder diffraction,X-ray fluorescence spectroscopy,electron probe,infrared spectroscopy and Raman spectroscopy.The composition,existing form and occurrence state of brucite are analyzed,and the possibility of physical impurity removal of brucite is discussed.The color of brucite samples from Xujiatai,Fengcheng,Liaoning Province is mainly yellow,green,brown,brown,black,massive structure and cryptocrystalline structure.The samples are leaf-like,scaly and fibrous aggregates with refractive index of 1.55-1.56,density of 2.37-2.47 g/cm 3,waxy luster,translucent-translucent.The samples were observed and analyzed by polarizing microscopy and scanning electron microscopy.Brucite mineral particles were mostly closely arranged in lamellar or irregular granular structure under scanning electron microscopy.Hexagonal lamellar structure particles with directional arrangement could be seen in the lamellar structure part.The particle size was about 1 micron,and its transparency was higher than that in the non-directional granular structure.Under polarizing microscopy,brucite mineral particles were interlaced in granular and fibrous shape.Most of the particles are in the range of tens to hundreds of micrometers.The cross-twisting of some particles indicates the transverse shear and longitudinal compressive stress during the formation process.The vein structure should be secondary crystallization of minerals after the stress action.Impurity minerals include brucite,serpentine,carbonated minerals,iron-bearing minerals,etc.Most of them are heteromorphic,and a few of them are semi-automorphic-automorphic.The particle size varies from several to several hundred microns.X-ray powder diffraction,X-ray fluorescence spectroscopy,electron probe,infrared spectroscopy and Raman spectroscopy analysis showed that besides brucite,there were also serpentine,magnesite,brucite,forsterite,plagioclase serpentine,magnesite,dolomite,calcite and other mineral components in brucite samples.The contents of iron,titanium,manganese,cobalt,silicon,calcium and aluminium in samples of different colors are different,and the types of impurity minerals are also different.