Allochromatic gems are gems that are colored by impurities. When they had been wholly pure, they would be colorless. The colour of all allochromatic gems is produced by defects. Therefore, all shade in corundum is brought on by defects. Clarity: Clarity is yet another noteworthy variable that refers to the https://www.tumblr.com/thegemjournal/759696203354128384/understanding-the-unique-characteristics-of-yellow?source=share