Mineralogic-petrographic analysis and gemological properties of tepeyurt (Tokat) jaspers

Within the scope of this master's thesis study, mineralogical, petrographic and gemological examinations of the jaspers in Tokat Province Tepeyurt (Topçam) region have been made. It is aimed to determine the jaspers that have the potential to be used as a cornerstone, to reveal the formation conditions and side rock relationships and to determine whether they can be evaluated gemologically. For this purpose, thin section, XRD, XRF, ICP-MS analyzes and gemological studies were carried out on samples taken from the study area. As a result of XRD analysis, the presence of quartz, hematite, calcite and pyrite were determined in the jasper samples. According to XRF analysis, SiO2 amount was 82.5% and Fe2O3 amount was 15.5%. As a result of ICP-MS analysis, 17648.00 ppm Cs, 41905.18 ppm Fe and 8246.81 ppm Mn were determined.. The jaspers in the study area were formed in late triassic aged green colored metavolcanic rocks. The sizes of the jaspers generally vary from a few cm to 1.5 meters, and their colors are dark red and brownish red depending on the hematite contained within. As a result of the gemological studies, it has been determined that the jaspers in the study area can be used as the cornerstone.