This research of yellow sapphires was determined by The dearth of clarity while in the literature as to the origin with the yellow coloration. In retrospect, this uncertainty was the results of 3 aspects. First, the Fe3+ concentration in natural stones spans A selection of approximately four–4750 ppma, but only https://www.tumblr.com/thegemjournal/759696203354128384/understanding-the-unique-characteristics-of-yellow?source=share