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The author studied how to distinguish Omphacite from Jadeite through using basic gemmologicalmethods such as visual observation，R．I．，S．G．，microscopic method，and also pertographic study throughthin sections together with XRD，UV-vis—NIR spectrophotometry，and FTIR methods．The preliminaryconclusion is：in order to distinguish jadeite from omphacite one could use visual observation：omphacite isdark to very dark green to opaque whereas jadeite can be colourless to pale or bright green；RI：omphacite is 1．68to 1．72 whereas jadeite is 1．65 to 1．67；SG：omphacite is 3．35 to 3．40 whereas jadeite is 3．33 to 3．36；and EDAX：jadeite should contain more than 80％Na compared to Ca，and more than 80％or 50％A1 compared to Mg+Fe2+ or to Fe3+ respectively．Any chemical compositions departing from this should not be called jadeite．