This research of yellow sapphires was enthusiastic by The shortage of clarity while in the literature as to your origin from the yellow coloration. On reflection, this uncertainty was the result of a few variables. First, the Fe3+ concentration in natural stones spans a range of close to 4–4750 ppma, https://www.tumblr.com/thegemjournal/759696203354128384/understanding-the-unique-characteristics-of-yellow?source=share