Bismuth, atomic element number 83, is an interesting metal with many unique properties.

It is almost as dense as lead but without the high toxicity. It is also one of the least thermally conductive metals but has a relatively low melting point (271°C, 520°F). When melted, bismuth can crystallize upon cooling into its signature stair-stepped square pattern. The iridescent colors are caused naturally by the oxidation of the surface as it cools in the air.

Bismuth is a key ingredient of Pepto Bismol. You can even extract it from the pink medicine with a little chemistry.

Bismuth was long thought to be a stable element, but in 2003 it was discovered to be very weakly radioactive. In fact, it’s radioactive decay is so weak, the half-life has been calculated to be longer than the current age of the universe.

This listing is for one rainbow bismuth crystal, sold by weight. Photos are representative of what you will receive, not the exact item. Please allow for natural variation in shape and color.