Characterization and economic potential of Afyonkarahisar-Seydiler gem-quality opals

Opals may form as volcanic or sedimentary in origin. The Seydiler region is geologically dominated by the volcanic activity, and the gem opals in this study area are the opals of sedimentary origin within the diatomite area. During the Miocene period, diatomite emerges from the water-borne microorganisms in the Seydiler region, which contains the lacustrine environment, through their diagenesis in the skeletons of silica-containing diatoms. As a result of the regional volcanic activity, the tuffite layer with diatomites, and later the formation of peri-chimney were formed in the region. This formation in this area was defined in the literature for the first time and named as d Seydiler Ooze. To elucidate the diatom and to dominate the morphology, macroscopic samples of three different pure diatomite layers were energised by X-ray spectrometer (SEM-EDX) and FEI Nova NanoSem 650 scanning electron microscope(İLTEM-DPU). Seydiler gem opal formation has been studied as ooze layer in Turkey and the world, but no gem opal formation has been found. Therefore, the necessity of scientific interest and research has led to detailed research. XRF, ICP-AES, XRD, FT-IR, DCµR spectroscopy and isotope analysis were performed for gem opal. Geochemical analysis of opal and stable oxygen isotope analysis of aleV-SMOW (‰) gave information about the environmental and temperature formation of the region. The upper parts of Seydiler ooze are overlain by Seydiler Ignimbrite and Karakaya basalts. It was determined that basaltic trachyandesitis was found by polarizing microscope and chemical analysis applied to Karakaya basalts. Seydiler gemstone features such as stonework opals, fire opal and Australian opal. Therefore, we think that it may have commercial potential for our country.