Allochromatic gems are gems which are colored by impurities. Whenever they ended up wholly pure, they'd be colorless. The colour of all allochromatic gems is made by defects. As a result, all color in corundum is because of defects. How to Choose Ideal Yellow Sapphire? According to Vedic Astro specialists, https://bookmarkforest.com/story18030362/sri-lankan-yellow-sapphire-an-overview