Bismuth is number 83 on the periodic table, this means that it is itself an element, it is its own thing. When bismuth starts its life it is a shiny grey silver colour, then when it is melted down and allowed to start to cool it starts to grow these stunning pyramid like shapes! The colours come from the heat reacting with the oxygen in the air to form different bands of colours (this is why you see some crystals that appear to radiate from one point, its because of the way they started to cool from that point or that was the last point to cool).
The carvings on the other hand are actually casts, where the hot melted bismuth is poured into a mould and allowed to harden, this created the stunning shaped pieces, such as starfish and turtles. the colours of these pieces are made using very secretive techniques involving heat, ambient temperature and air pressures.
Bismuth Display Pieces
Bismuth Carvings
Bismuth Natural Shapes

Bismuth