Allochromatic gems are gems which can be colored by impurities. If they had been wholly pure, they might be colorless. The color of all allochromatic gems is produced by defects. So, all shade in corundum is a result of defects. Pukhraj stones are believed to get effective talismans that deliver https://www.tumblr.com/thegemjournal/759696203354128384/understanding-the-unique-characteristics-of-yellow?source=share