Ceylon Yellow Sapphire gemstones are deemed a good choice as they are Just about totally clear on the bare eye i.e. ‘eye-clean'. They cannot be totally free from inclusions and crystal or feathers are those normally located in natural Ceylon Yellow Sapphires. Certification: The presence of a credible gemological certification https://www.tumblr.com/thegemjournal/759696203354128384/understanding-the-unique-characteristics-of-yellow?source=share