Preliminary studies to distinguish omphacite from jadeite
- 作者：Panjawan ThanasuthipitakTay Thye SunWilawan AtichatHenry A.H(a)nniTheerapongs Thanasuthipitak
- 会议时间：2011-09-01
- 关键词：jadeite ; Omphacite ; distinguish
- 作者单位：Panjawan Thanasuthipitak,Theerapongs Thanasuthipitak(Dept Geol Sci,Chiang Mai University,Chiangmai,Thailand)Tay Thye Sun(Far East Gem Lab,360,Orchard Road#09—04,International Building,Singapore 238869)Wilawan Atichat(GIT,Gemmological Research and Testing uilding,Faculty of Science,Chulalongkorn University,Phayathai Road,Bangkok 10330,Thailand)Henry A.H(a)nni(GemExper GmbH,Postfach 921,CH4001,Basel,Switzerland)
- 母体文献：玉石学国际学术研讨会论文集
- 会议名称：玉石学国际学术研讨会
- 会议地点：北京
- 主办单位：中国珠宝玉石首饰行业协会
- 语种：chi
- 分类号：G
摘要
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.