The use of Kröger-Vink notation eradicates various other conceptual reaction options because of the necessity of both demand and web site harmony. Certification: The presence of a credible gemological certification from a reputable and identified gem laboratory adds believability and assurance to the quality of yellow sapphire or another gemstone. https://www.tumblr.com/thegemjournal/759696203354128384/understanding-the-unique-characteristics-of-yellow?source=share