Celebrate National Science Day 2019: Make real bismuth crystals!

Cool science stuff! -- Bismuth is a chemical element with symbol Bi and atomic number 83. It is a pentavalent post-transition metal and one of the pnictogens with chemical properties resembling its lighter homologs arsenic and antimony. Elemental bismuth may occur naturally, although its sulfide and oxide form important commercial ores.

Bismuth is one of the easiest and prettiest metal crystals that you can grow yourself. The crystals have a complex and fascinating geometric hopper form and are rainbow-colored from the oxide layer that quickly forms on them.

Although bismuth is much less toxic than other heavy metals, it's not exactly something you want to eat. Using steel measuring cups, it's best to only use them for the bismuth project and not for food.

The quality of crystals obtained depends in part on the purity of the metal, so we'll use bismuth, not an alloy. One way to be certain of the purity is to remelt a crystal of bismuth. It can be used over and over again.