Allochromatic gems are gems that are coloured by impurities. When they were being totally pure, they would be colorless. The colour of all allochromatic gems is made by defects. As a result, all shade in corundum is because of defects. Burma is renowned for making a wide array of treasured https://greatbookmarking.com/story18098052/a-simple-key-for-natural-yellow-sapphire-from-sri-lanka-unveiled