This analyze of yellow sapphires was enthusiastic by The shortage of clarity within the literature as into the origin of the yellow coloration. On reflection, this uncertainty was the result of 3 variables. 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