The ruby encloses the brilliant red of the clouds of evening… – Charles Blanc, Art in Ornament and Dress, 1875, translated from French

[T]he diamond and other precious stones are focuses of light, and essences of colour which seem expressly created to ornament on a small scale the human body with all the splendours which adorn the universe on a large scale. – Charles Blanc, Art in Ornament and Dress, 1875

There is in them a softer fire than the ruby, there is the brilliant purple of the amethyst, and the sea green of the emerald – all shining together in incredible union. Some by their splendor rival the colors of the painters, others the flame of burning sulphur or of fire quickened by oil. – Pliny, about the opal