Wismut

Bismuth grows as a hopper crystal: the edges race ahead, the faces lag behind, and stepped terraces arise. The crystals here grow in exactly this way – the length gains step by step, the width follows softly.

A thin layer on the surface recolours the light depending on the viewing angle, like the tarnish colours on real bismuth. A slow ring pulse makes the steps all around grow by one step; a touch does the same, only more strongly.

How a crystal grows is decided by its lattice — in bismuth this rule can be seen as a staircase. The museum itself is about exactly that: the permanent exhibition “Das weiße Wunder” at the Westfälische Salzwelten leads into underground vaults full of crystals that formed more than 250 million years ago, shows their lattice structure under salt microscopes and tells how brine becomes salt on the Hellweg — Bad Sassendorf is an old salters' town.

“Wismut” can be experienced at the Ferromone family festival “Farbexplosion” at the Westfälische Salzwelten, Bad Sassendorf – on Saturday, 17 October 2026, 6 to 10 pm.

Placement in the post-digital model of positing

The staircase shows the rule by which the crystal grows: edges first, faces after. The tarnish colour comes not from the body but from the viewing angle — the same form, posited differently depending on the standpoint.