In others it grows outward in the curving shapes called gypsum flowers — delicate, petal-like structures that defy gravity, extending from the rock surface in spirals and curves as though frozen in the act of blooming.

In still others it accumulates as crystals or as the blistered formations called cave popcorn that cover certain ceilings.

The gypsum forms because sulfate-bearing water — originating from the oxidation of pyrite in the rock above — moves very slowly through the limestone and deposits calcium sulfate as it goes.

In the dry upper passages, where no liquid water is present to dissolve what forms, the gypsum builds up over millennia.

Some of the formations visible in the cave today took thousands of years to develop.