This research of yellow sapphires was determined by The dearth of clarity inside the literature as towards the origin with the yellow coloration. On reflection, this uncertainty was the results of 3 aspects. 1st, the Fe3+ concentration in natural stones spans A selection of about 4–4750 ppma, but only concentrations https://digibookmarks.com/story18050807/the-definitive-guide-to-natural-yellow-sapphire-from-sri-lanka