A Study Of The Causes And Gemological Significance Of Secondary Weathering Kingfisher Color Jadeite

As a secondary color,Jadeite's kingfisher color has different existent forms,concrete forms and mode of origin in Jadeite gravel of different attitude.Jadeite's kingfisher color has been divided into two types according to its occurrence and its characteristics in this paper.Firstly,Jadeite's kingfisher color originating in direct penetration of Iron oxide is most common in Pun Shan Shek of elluvium-deluvial Jadeite deposits and Waterstone of present riverbed.Secondly,Jadeite's kingfisher color originating in the secondary weathered is most common in secondary weathered Sandstone and secondary weathered Waterstone.The distribution features of Jadeite's kingfisher color in Jadeite gravel are as follows which originating in the two times of weathering.1)Color zoning characteristics:It has obvious horizontal zoning from Jadeite's yellow crust,red fog,secondary grey-green beds to primary Jadeite;2)The distribution features of Jadeite's kingfisher color:It is the best transparent in the whole Jadeite which is Jadeite's red kingfisher color;3)Secondary green color will be found in jadeite of red kingfisher color;4)There is a obvious boundary between Red kingfisher color and Secondary green color.We can find that the part filled with secondary green color will be oxidized into an obvious iron oxide enriched layer—Red kingfisher,where no secondary green color will become yellow weathered layer after oxidation in the secondary weathered Jadeite gravel.At the same time,there are yellowing in cheap secondary green color Jadeite.Namely,secondary green color Jadeite exposed to the air for a long time will be oxidized into yellow rust silk,yellowing and turning yellow.Combined with artificial oxidative experimental result that secondary green color will turn yellow or red during heating.Then we can know that Fe³⁺in the secondary weathered Jadeite gravel comes from minerals such as chlorite containing Fe²⁺that have penetrated into the surface and interior of the Jadeite.Infrared spectrum analysis combined with the observation of the gem microscope and polarizing microscope,we know that the red kingfisher is produced by colloidal limonite which is distributed in the gap and microfissure of the Jadeite granules.I simulated the formation process of the secondary weathering kingfisher by the permeability diffusion experiment of aqueous solution,found that the color concentration,transparent layer and stratification are covered at the edges of watermark.According to the similarity between the two phenomena and the distribution characteristics of aqueous solutions in paper fibers similar to that of kingfisher color in Jadeite gravel.I suspect that the iron oxides of jadeite will enter into the interior of jadeite through capillarity,the concentration of water and Fe³⁺will occur at the boundary and form delamination.Therefore,I think the cause of the secondary weathered kingfisher color is that minerals such as chlorite containing Fe²⁺penetrated into the surface and interior of the Jadeite are subjected to surface weathering during the surface uplifting process and form limonite after oxidation.Then limonite with aqueous solution by capillary enters into the interior of jadeit e.Limonite and moisture are concentrated at the boundary,resulting in better transparency of secondary weathered kingfisher color and the clear boundary between red kingfisher and secondary green color.Through the research on the causes of the secondary weathered kingfisher color,it can provide reference for gambling stone identification,application in finished products and the identification of true and false colors.