This research of yellow sapphires was enthusiastic by The shortage of clarity inside the literature as on the origin with the yellow coloration. On reflection, this uncertainty was the result of a few aspects. To start with, the Fe3+ focus in natural stones spans a range of approximately 4–4750 ppma, https://www.tumblr.com/thegemjournal/759696203354128384/understanding-the-unique-characteristics-of-yellow?source=share