This analyze of yellow sapphires was enthusiastic by The shortage of clarity in the literature as to your origin on the yellow coloration. In retrospect, this uncertainty was the result of a few components. First, the Fe3+ concentration in natural stones spans A selection of close to 4–4750 ppma, but https://www.tumblr.com/thegemjournal/759696203354128384/understanding-the-unique-characteristics-of-yellow?source=share