Bismuth Crystal

Reduced to clear, packaging varies from that shown. 

Bismuth, 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). When melted, bismuth can crystallise upon cooling into its signature stair-stepped square pattern. The iridescent colours are caused naturally by the oxidation of the surface as it cools in the air.

Each piece varies in size and will look unique, but they'll all weigh 60 to 80 grams.