This review of yellow sapphires was determined by the lack of clarity in the literature as on the origin of your yellow coloration. On reflection, this uncertainty was the results of 3 factors. First, the Fe3+ concentration in natural stones spans An array of close to 4–4750 ppma, but only https://www.tumblr.com/thegemjournal/759696203354128384/understanding-the-unique-characteristics-of-yellow?source=share