Influencing Factors Of Jadeite Quality In An Area Of Russia

With the development of jadeite market,the high-quality jadeite produced in Burma is increasingly lack.Among the other producing areas in the world,the output and quality of Russian jadeite have some advantages and great potential.This paper studies the influencing factors about the quality of Russian jadeite and discusses the influence of mechanism about it.In order to provides basic data for enriching the gemological characteristics of jadeite in an area of Russia and promoting the development of the resources.The most of Russian jadeites were mainly in green and grey-green.The polished surfaces are vitreous luster;translucent to micro transparent.Refractive index is 1.65to 1.66(point measurement).The Mohs hardness is around 6.5 to 7.The relative density is between 3.06 and 3.32 g/cm~3.The relative density of individual samples is low due to the existence of secondary mineral calcite,natrolite and so on.When the samples were observed under polarized light microscope,it was found that the samples were mostly in granular or short columnar texture.Most samples'mineral particles are coarse grained and not tightly integrated.But longer columnar texture and fibrous texture were also observed in some samples.The texture of these parts is smoother than others.The Secondary products mostly exist in the gaps between cracks and particles,which seriously affect the transparency.The mineral chemical composition of Russian jadeite samples was tested by electron probe.It was found that the main composition of minerals is jade and omphacite.In some samples,phlogopite,natrolite,sphene,maucherite,celsian and clinoptilolite were tested.Among them,phlogopite and maucherite have a certain indicative effect on the occurrence of Russian jadeite samples from ultrabasic rocks.In addition,the collected samples were tested by the infrared spectrometer,and the main components of Russian jadeite were jadeite and omphacite.Absorption lines at 437nm can be measured by using the uv-visible spectrum.According to the analysis of test results,the main factors affecting the quality of Russian jadeite include texture,mineral composition and mineral chemical composition.The texture mainly affects in four aspects:grain size,mineral form,mineral combination mode and fracture.In terms of mineral composition,the color of jadeite will be dark if omphacite exist.Jadeite in Burma is pure jadeite,while the mineral of Russian jadeite is co-existed by jadeite and omphacite.Mineral chemical composition mainly affects its color.The presence of Cr makes it greener,but too much Cr will reduce the transparency of the sample.