This review of yellow sapphires was determined by the lack of clarity during the literature as to your origin on the yellow coloration. On reflection, this uncertainty was the result of 3 things. Initially, the Fe3+ focus in natural stones spans A variety of roughly 4–4750 ppma, but only concentrations https://www.tumblr.com/thegemjournal/759696203354128384/understanding-the-unique-characteristics-of-yellow?source=share