Study On Gemological And Spectral Characteristics Of Ambers And Imitations From Several Different Localities

Amber is a kind of natural organic compounds which is formed by the resin fromThe Mesozoic Cretaceous to Tertiary with complex geological processes andfossilization.Using the ambers from Baltic Sea, Dominica, Burma, Fushun and theirimitations as the research objects, the paper has been done some research ongemological and spectral characteristics mainly through using modern testing methodssuch as microscope and analysis of Ultraviolet Fluorescence, Infrared Spectroscopyand Nuclear Magnetic Resonance. The purpose is to analyze the types andcharacteristics of carbon functional groups in amber, and to find the differencesbetween ambers from different localities and imitations, which can provide ascientific basis for the identification and study of ambers.Amber is a fossil resin, while the natural resin is a fossil resin that lack offossilization. The difference in maturity results in the difference in the saturation ofchemical bond of organic compounds. In IR spectrum, the absorption peak in therange of1705-1728cm-1is caused by the functional group of C=O stretching vibration.The absorption peak positions of ambers from different localities are slightly different.The cause of this difference may be ambers’ different geological time, environmentand species of trees.The IR spectrum of reconstituted amber is close to that of natural amber.Therefore, they cannot be distinguished only by IR testing. The IR testing resultsshould be combined with the microscope examination, which is used for finding thetypical "blood" structure in reconstituted amber. The IR spectrum of natural resin hasabsorption at3078cm-1which is caused by C-H stretching vibration, while ambersamples have not. The types and quantities of functional groups are different betweensynthetic resin and amber. So they can be distinguished effectively by IR spectrum.Nuclear magnetic resonance is mainly used for the determination of the molecular structure of amber. Using13C solid nuclear magnetic resonance technology, thetesting can obtain the carbon skeleton information. The purpose is to analyze theforming environmental differences of ambers that from different localities and periods,and to research the changes of carbon functional group in amber along with its agegrowth. With different maturity, the spectrum of amber and natural resins are differentin the zone of unsaturated carbon resonance signals (δ=100×10-6-160×10-6). So itcan be used as an auxiliary basis for identification of ambers and natural resins. Butthe organic compositions of ambers and natural resins are very complex, and somesamples’ compositions are slightly different. The analysis of the13C nuclear magneticresonance can reflect chemical structure to a certain degree, but it is not universallyapplicable. So the13C nuclear magnetic resonance had better be combined with othertest methods in identification.