Emerald is a chromium-containing emerald green beryl, usually together with diamonds, hồng ngọc và ngọc bích, it is listed as the four most precious gems. The ancient Roman naturalist Pliny (Gaius Cecilius Secundus, Về 23-79 QUẢNG CÁO) once gave a wonderful description of the color of emeralds: “There is no gem that is more pleasing to the eye [...]
