| Abstract [eng] |
SUMMARY KRISTIJONAS UNDZĖNAS IDENTIFICATION OF THE FELDSPAR GROUP ISOMORPHIC ROW MEMBERS USING GEMOLOGICAL METHODS The main objective of this dissertation is to assess the gemological methods affectivity and reliability for the identification of feldspar group minerals. The main task of this dissertation is to investigate and identify minerals of the feldspar group by using gemological investigation methods. After that to the part of the samples, which are representing the different kind of feldspar group minerals, to make crystal chemical analysis in Vilnius chemistry Institute. And after that to compare the results of the crystal chemical analysis and gemological investigation methods. Thereby to assess the affectivity and reliability of the gemological investigation methods in identification of feldspar group minerals. In this dissertation there were 86 minerals of the feldspar group investigated. 56 samples were identified like plagioclases and 30 were classified to the alkaline feldspar subgroup. From the plagioclases group there were indicated 32 Labradorites, 17 oligoclases, 4 albites, 3 andesines. And from the alkaline feldspar, there were 6 amazonites, 2 microclines, 22 orthoclases. Proceeding the job, there were made next finding: 1. It is easily possible to separate the plagioclases subgroup from the alkaline feldspar subgroup minerals, even to indicate the approximate plagioclase number, by using the gemological methods. 2. Performed crystal chemical analysis results proves the affectivity and reliability of the gemological investigation methods for the identification of feldspar group minerals. 3. For the precision of the results, then using the gemological methods for the identification of feldspar group minerals, the samples should have next features: the weight of the sample should be more than 0,5 g., the samples should be without the inside defects and indiscrete mineral composition. |
