This review of yellow sapphires was motivated by The shortage of clarity during the literature as towards the origin of the yellow coloration. Looking back, this uncertainty was the results of three aspects. Very first, the Fe3+ concentration in natural stones spans A selection of somewhere around 4–4750 ppma, but https://www.tumblr.com/thegemjournal/759696203354128384/understanding-the-unique-characteristics-of-yellow?source=share