he grading and evaluation standards of rubies are mainly based on 1T and 4C: Deursigtigheid, Kleur, Helderheid, Snit, and Carat. 1. Deursigtigheid: 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: deurskynend, translucent, translucent, sub-translucent, and opaque. […]
