Allochromatic gems are gems which might be coloured by impurities. Whenever they ended up entirely pure, they'd be colorless. The color of all allochromatic gems is made by defects. So, all shade in corundum is attributable to defects. Certification: The presence of a credible gemological certification from a respected and https://ledbookmark.com/story3573926/top-latest-five-buy-sri-lanka-pukhraj-in-india-urban-news