This research of yellow sapphires was inspired by the lack of clarity while in the literature as for the origin of your yellow coloration. In retrospect, this uncertainty was the result of 3 elements. 1st, the Fe3+ focus in natural stones spans a range of about four–4750 ppma, but only https://www.tumblr.com/thegemjournal/759696203354128384/understanding-the-unique-characteristics-of-yellow?source=share