he grading and evaluation standards of rubies are mainly based on 1T and 4C: Transparence, Couleur, Clarté, Couper, et carat. 1. Transparence: refers to the degree to which a gemstone allows visible light to pass through. In the visual identification of rubies, transparency is generally divided into five levels: transparent, translucide, translucide, sub-translucent, et opaque. […]
