This research of yellow sapphires was enthusiastic by The shortage of clarity during the literature as on the origin of your yellow coloration. On reflection, this uncertainty was the result of 3 factors. To start with, the Fe3+ concentration in natural stones spans An array of close to four–4750 ppma, https://www.tumblr.com/thegemjournal/759696203354128384/understanding-the-unique-characteristics-of-yellow?source=share