Turkish Blue Chalcedony beads are a cryptocrystalline Quartz variety which is naturally blue to violetish blue in hue and is semi-translucent to opaque with a glass or waxy luster. Named for the ancient maritime city of Chalcedon (now Kadikoy), on the Sea of Marmara in modern Turkey - this gemstone is presently mined in Turkey, Brazil, India, Madagascar, Namibia, Zimbabwe, Sri Lanka (Ceylon), Uruguay and California.