Bismuth - Bi
This is a sample of three pellets of bismuth, 10 grams each, with a purity of 99.99% and the shot is ultra-pure bismuth with a purity, better than 99.999%. Bismuth is a silvery metal, with a slightly yellowish hue. When it is oxidized, then it becomes somewhat darker, as the shot shows. If the surface of a sample of bismuth is polished like a mirror, then the oxidation layer can give rise to beautiful colors. With a somewhat rougher surface, the oxide layer makes the metal appear grey.
Bismuth is a very brittle metal, which can have a beautiful crystalline appearance. Below, a piece of approximately 10 grams is shown, with one side, which was exposed to air for a long time, and the other sides being splintered from a larger piece. This shows how shiny the metal is, and it shows the crystalline appearance.
When bismuth melts and slowly solidifies, then it can form beautiful crystals with remarkable colors. The picture below shows such a crystal. The colors are due to the presence of a very thin oxide layer, which is so thin, that its thickness is in the order of magnitude of the wavelength of light. This causes all kinds of interferences at the surface and produced many different colors.
A little video is made, which shows the same crystal, rotating slowly. The download size of this video is approximately 9 MByte.