We made bismuth oxide crystals, following a tutorial.

The bismuth melts at a very low temperature, and so a steel pot and butane burner are all that we needed to get started. We checked to see how much of the bismuth had re-solidified by blowing on the surface—we avoided shaking the pot, as this can disrupt the formation of larger cubic crystals. Once half or so of the pot has congealed, I poured off the remaining liquid bismuth to reveal the crystal structures. The bismuth oxide layer forms almost instantly upon cooling.