Petrographic and gemological investigation of neogene aged opals close to Akyokuş-Sarayköy (Konya)

In this study, Akyokuş-Sarayköy (Konya-Turkey) and its surroundings are located. In the study area, nodular opal formations of workable quality were found in the southwest of Sarayköy. The Mesozoic aged Lorasdağı formation (Jurasic-Cretaceous) and Hatip Ophiolitic mélange (Upper Cretaceous) are mainly located in the study area. Late Miocene -Early Pliocene lacustrine series overlie the older rocks. At the base of the lacustrine series, the Sille formation, which consists of fluvial deposits, is unconformably observed on the foundation. Insuyu formation conformably overlies the Sille formation. The İnsuyu formation is in lateral and vertical transition with the volcanoclastic rocks (Küçükmuhsine formation) developed due to the volcanic activity in the region. Yörükler formation overlies volcanoclastic rocks conformably/incongruously. These units are unconformably overlain by the Quaternary Topraklı formation. All rocks are unconformably covered by Alluvium. Opal formations in the Konya region are associated with the volcanic rocks in the region (Erenler Volcanics). It has occurred especially in close association with the fluids that make up the geyserites. Opals are observed in a zone about 25 meters thick in the region. Quartz and chalcedony were observed as a result of mineralogical and petrographic studies made from agate. On average, agate contains 92.6% SiO2, 2.6% Fe2O3, 0.8% MgO, 0.8% CaO, 0.19% Cr2O3, 0.2% K2O, 0.6% NiO. Chalcedony, quartz and calcite were detected in the gemological examinations of slices and cabochons obtained by cutting from Opla tubers. Good quality rosaries, necklaces, earrings, table name holders, bracelets and other ornamental objects were produced from opals. Opal formations detected in the study area can be evaluated economically.