Bismuth crystals are beautiful, with their colors and staircase shaped structure. But why is bismuth so colorful? The answer is surprisingly simple. Rust.
Rust (or oxidation in scientific terms) occurs in all metals. (Oxygen is a rather nasty substance in some cases!) When bismuth oxidizes, the bismuth oxide now coating the outside separates different wavelengths of light. The thickness of this bismuth oxide determines the qualities of the colors reflected.
Growing bismuth crystals at home has become more popular. For a metal, bismuth has a fairly low melting point. If you don't mind ruining a pan or two, you can melt it on your stove. For the best results, make sure your bismuth is pure. There are plenty of guides to doing this elsewhere on the internet.
The staircase structure of bismuth is due to its crystals having a higher growth rate towards the edges as opposed to the inside face.
Bismuth's natural color is a fairly bland metallic gray. Bismuth oxide is the colorful one.
Beautiful bismuth crystal
Some very un-pure bismuth
Those colors are awfully similar to bismuth. Why could that be?
Rust/oxide isn't always so pretty.
Bismuth is used in stomach medicine
Bismuth is on the periodic table.
“Bismuth's natural color is a fairly bland metallic gray.”
The crown jewel of rock shops in the Chicago area is undoubtedly Dave's Down to Earth Rock Shop. The place has its own museum with some impressive specimens and has a diverse stock of rocks and minerals for all ages.