This study of yellow sapphires was determined by the lack of clarity within the literature as to your origin in the yellow coloration. On reflection, this uncertainty was the results of a few variables. Initial, the Fe3+ concentration in natural stones spans An array of roughly 4–4750 ppma, but only https://www.tumblr.com/thegemjournal/759696203354128384/understanding-the-unique-characteristics-of-yellow?source=share