Our results revealed that UV lighting turned pastel colors into orange on certain stones. We bought a UV light and tested it out for ourselves. These color centers can also be effected by UV lighting.

I spoke to some senior gemologists in the trade, who were aware of such a phenomenon in yellow sapphires that called “trapped color holes.” As far as they knew, this was not something recognized in other fancy colored sapphires. Going forward, we decided to do our own testing on our stones. After multiple trade shows, we noticed the stone stayed under strong showcase lighting, it seemed feasible that this had an effect on color. Soon as a I began to investigate and piece together what happened to my stone, I had a eureka moment. This practice would apparently improve color saturation. (emphasis added).īefore labs knew anything, there were rumors about foreign gem dealers leaving their stones out in the sunlight before attending trade shows. If the stone has been dyed, coated, painted, varnished or sputtered. shifting to pink) by a colour stability testħ. the colour of the stone is not stable and shifting out of the padparadscha colour range (e.g. the stone has been treated by irradiationĦ. If the stone has been treated as described in Information Sheets #2 and #3ĥ. The presence of yellow or orange epigenetic material in fissure(s) affecting the overall colour of the stoneĤ. If the stone has major uneven colour distribution when viewed with the unaided eye and table up +/- 30°ģ. While color alone as noted above can show the subtleties between orange and pink and padparadscha, a recent phenomenon has revealed that certain sapphires may appear as padparadscha at first, but fade over time into a pastel pink colored sapphire.Īs a result, the LMHC in its Information Sheet #4 Publication updated the list of Padparadscha disqualifications:ġ.If the stone has any colour modifier other than pink or orangeĢ. The difference between padparadscha sapphire and a fancy sapphire:

Dark sapphire stone