This research of yellow sapphires was inspired by the lack of clarity from the literature as on the origin from the yellow coloration. On reflection, this uncertainty was the results of three components. To start with, the Fe3+ concentration in natural stones spans A variety of close to four–4750 ppma, https://www.tumblr.com/thegemjournal/759696203354128384/understanding-the-unique-characteristics-of-yellow?source=share