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Raman Spectroscopy On Gem-Quality Microcrystalline And Amorphous Silica Varieties From Romania, Dana Pop, Ciprian Constantina, Dan TăTar, Wolfgang Kiefer
Raman Spectroscopy On Gem-Quality Microcrystalline And Amorphous Silica Varieties From Romania, Dana Pop, Ciprian Constantina, Dan TăTar, Wolfgang Kiefer
Studia UBB Geologia
Previous micro-Raman investigations on a wide range of types of microcrystalline silica samples have evidenced the presence of a new silica polymorph, i.e. moganite, in virtually every sample. In order to test the ubiquity of moganite in such geological materials in Romania, micro-Raman measurements were performed on gem-quality microcrystalline quartz (chalcedony, including agate and jasper) and additionally on quasi-amorphous silica (opal, silicified wood) samples from different occurrences. All the studied materials, including the quasi-amorphous varieties contain moganite in variable amounts (from traces up to local concentrations of 75 wt. %). Establishing correlations between colour and texture of the chemically-“pure” micro-crystalline …
Evaluation Of Pgaa Data For Provenance Of Lithic Artifacts, Otis N. Crandell
Evaluation Of Pgaa Data For Provenance Of Lithic Artifacts, Otis N. Crandell
Studia UBB Geologia
The objectives of the study were to determine whether Prompt Gamma Activation Analyses (PGAA) could be successfully used to trace the source(s) of various Neolithic artifacts made of microcrystaline quartz. Two macroscopically identical sources of jasper from central and western Romania were analyzed by PGAA along with five Neolithic artifacts from the Limba site (Alba County). Due to the limited number of trace elements, which can be measured by PGAA, this method when used alone might produce inconclusive results for discriminating between jaspers from different sources. The interpretation of the data may be used for general assessments of provenance involving …