Allochromatic gems are gems which can be coloured by impurities. When they have been totally pure, they'd be colorless. The colour of all allochromatic gems is produced by defects. Thus, all shade in corundum is attributable to defects. What are you looking ahead to? Go on and a dash of https://socialmarkz.com/story8431675/an-unbiased-view-of-sri-lankan-yellow-sapphire-price-in-india