Chemistry crafts: crystals!

This isn’t actually a discovery. It’s something you can do at home. All you need is bismuth, a pot and a stove and you can grow your own crystalline rainbow skyscrapers:

The Amazing Rust blog:

The distinctive, ‘hoppered’, shape of a Bismuth crystal results from a higher growth rate around its outer edges than on its inside face. The higher rate of growth on the edges forms a crystal which appears to be partially hollowed out in a rectangular-spiral stair step design.

The crystal’s eye-catching array of colors results from the formation of a thin oxide layer on its surface…. Due to variations in the thickness of the oxide layer, the crystal is not one solid color but rather is a rainbow of colors corresponding to the wavelengths (and colors) of light which interfere constructively at each location.

In not so many words:

There’s a “how to make your own” lesson at the link.