Chalcedony is the group name for many multicolored mineral gemstones. We know chalcedony in its more familiar forms as onyx when it’s black, carnelian when it’s red, or chrysoprase when it’s green. When chalcedony is blue, it’s simply called blue chalcedony. That is, until it turns white.
Yes, blue chalcedony, with its stunning blue color, can fade. The beautiful sky blue color can turn to an opaque or chalky shade of white. This happens particularly in blue chalcedony beads when left out in the open, unwrapped or uncovered for months. The fading is not the fault of the stones, the miners who mined them, or the people who sold them. It’s the nature of blue chalcedony’s fibrous crystals that causes the fading on prolonged exposure to ordinary light.
Over a period of six months, a blue chalcedony necklace and earrings of my own design were exposed in the ambient light of my studio and the jewelry stores where they were displayed. They were not illuminated by strong lighting, nor were they exposed to heat. But, neither were they wrapped up in cloth or plastic, nor stored in a closed drawer or jewelry box during those months.
The light blue chalcedony stones in the necklace and earrings turned to white in varied degrees, with some stones losing their blue color more than others. Some stones turned white, a few lightened a lot, and others became only a lighter blue. But, all of the blue chalcedony stones faded to one degree or another. The slideshow documents the changes.
Why does this happen? We know that blue chalcedony is a silicon dioxide gemstone in a fine-grained fibrous form of quartz. Physics suggests that the blue color comes from the scattering of light within the fibrous crystals – something like the sky looking blue on a clear day wherein sunlight is captured, then scattered in the blue wavelength, by ice crystals in the atmosphere. Similarly, blue chalcedony looks blue because of light captured, then scattered in the blue wavelength, by the gemstone’s fibrous crystals.
It took only ambient low energy, i.e., ordinary light over a period of time, to change the crystal structure of blue chalcedony enough to change their pattern of light scattering. Crystals formerly scattering blue wavelengths were now scattering all wavelengths, or white.
Whether or not that reason is right, the take-away for jewelers and jewelry lovers alike is to store jewelry made of blue chalcedony beads in a drawer or wrapped in cloth. While wearing for one day, or even many, will not lighten your blue chalcedony jewelry, be advised to store it in a jewelry box, or under wraps when not wearing.
Your blue chalcedony jewelry will remain colorful as the day it was designed, if you store it properly. Unless, of course, you want it white.