This examine of yellow sapphires was enthusiastic by the lack of clarity inside the literature as to the origin of the yellow coloration. In retrospect, this uncertainty was the result of a few elements. Very first, the Fe3+ concentration in natural stones spans A selection of around 4–4750 ppma, but https://www.tumblr.com/thegemjournal/759696203354128384/understanding-the-unique-characteristics-of-yellow?source=share