he grading and evaluation standards of rubies are mainly based on 1T and 4C: Åpenhet, Farge, Klarhet, Kutt, og Carat. 1. Åpenhet: 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: gjennomsiktig, gjennomskinnelig, gjennomskinnelig, sub-gjennomsiktig, og ugjennomsiktig. [...]
