Bismuth forms pretty crystals when cooling, and is non-toxic. opit wanted to try combining bismuth crystals with ceramics, so she melted some bismuth in a stainless steel cup and poured it into ceramic forms. First we gnawed off a couple of pieces from the ingot:

A simple electric stove from the biolab was enough to melt the metal:

We also heated the ceramic forms in sand – when bismuth cools slowly, the crystals grow larger.

After pouring the metal, we waited until it has mostly solidified – with just a little rippling in the middle. Then the molten metal was poured back into the steel cup, revealing the crystals underneath.