CAN science explain the coloring of gems? Everybody knows that the white light which reaches us from the sun and other heavenly bodies can be decomposed into a number of colored rays by passing it through a triangular prism. A child blowing a soap bubble produces colors as splendid, in fact, a thin plate of any transparent substance whatever becomes colored under white light. Striated surfaces also offer effects not less brilliant; so that, to clothe certain insects more vividly, nature has grooved the tissue that envelops them. The rainbow, which the sun paints in so many colors in the drops of the falling shower, is the transcendent effects of decomposed light. Nature, with a palette, so to speak, charged only with white, knows the art of spreading over all her pictures the magic and glow of the most brilliant coloring. But we have not exhausted all the resources of this coloring, the secret of which is the light itself, here science is at fault; and we must still say what Huyghens said at the end of the seventeenth century, "In spite of the labors of Newton, no one has yet fully discovered the cause of the color of the bodies." We must then admire, without penetrating their secret, the peerless red of the oriental ruby, the pure yellow of the topaz, the unmingled green of the emerald, the soft blue of the sapphire, and the rich violet of the amethyst. 

Journal of Chemistry.