Chalcedony. A semi-treasured gemstone named after the close by city of Chalcedon, and is bought in many of Istanbul's large number of jewellery retailers. Targeted visitors can be quite bad, it might take an hour to get a few km in the old town. You could be improved off using https://andresznxud.blogadvize.com/44880891/the-fact-about-istanbul-personal-portfolio-wordpress-theme-that-no-one-is-suggesting