This examine of yellow sapphires was enthusiastic by The shortage of clarity during the literature as to the origin of the yellow coloration. In retrospect, this uncertainty was the results of a few things. 1st, the Fe3+ concentration in natural stones spans An array of roughly four–4750 ppma, but only https://www.tumblr.com/thegemjournal/759696203354128384/understanding-the-unique-characteristics-of-yellow?source=share