This analyze of yellow sapphires was enthusiastic by The shortage of clarity while in the literature as into the origin of the yellow coloration. In retrospect, this uncertainty was the results of three components. First, the Fe3+ concentration in natural stones spans a range of roughly four–4750 ppma, but only https://www.tumblr.com/thegemjournal/759696203354128384/understanding-the-unique-characteristics-of-yellow?source=share