This review of yellow sapphires was motivated by The shortage of clarity during the literature as to your origin in the yellow coloration. Looking back, this uncertainty was the result of a few things. Initial, the Fe3+ concentration in natural stones spans A selection of roughly 4–4750 ppma, but only https://www.tumblr.com/thegemjournal/759696203354128384/understanding-the-unique-characteristics-of-yellow?source=share