Extract from GIA Textbook by eClarity | Aug 3, 2018 | Uncategorized | 0 comments The GIA Color Scale begins with D (colorless) and continuous through the alphabet to Z (light yellow). A diamond’s color grade is based on the tone and saturation of its color, or its absence of color. Courtesy: #GIA. Photo: Tino Hammid/GIA Resource: Amanda Koo #eClarity. Submit a Comment Cancel replyYour email address will not be published. Required fields are marked *Comment Name * Email * Website Save my name, email, and website in this browser for the next time I comment.