Blue chalcedony is microcrystalline quartz in soft, misty blue — a gentle glow rather than a sparkle, at its best in generous cabochons. Fine material from Namibia and Turkey shows a subtle adularescent haze. Hardness about 7 makes it thoroughly practical.When in stock, each blue chalcedony at GEMIC Institute is natural, certified by our Siem Reap laboratory, and photographed as the exact piece for sale. Ask us about current availability.