The violet of the amethyst represents the deep purple shade of the heavens… – Charles Blanc, Art in Ornament and Dress, 1875, translated from French

As though pure white snow flashed and sparkled with the color of bright ruddy wine, and was overcome by this radiance. – Author unknown, about opal

[T]he hyacinth is like the tints of dawn passing from saffron to orange. – 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