Allochromatic gems are gems that happen to be coloured by impurities. When they have been totally pure, they would be colorless. The colour of all allochromatic gems is produced by defects. So, all shade in corundum is brought on by defects. Precisely what is most unusual is usually that this https://socialupme.com/story3514702/the-definitive-guide-to-natural-yellow-sapphire-from-sri-lanka