3.1" Spectacular Sulfur Crystals on Fluorescent Aragonite - Italy

The chemical composition of this vibrant mineral is S8, eight sulfur atoms bonded together to form a sulfur molecule. The crystal structures are typically tabular or blocky dipyramids that form in sedimentary rock.

One note on handling: sulfur crystals can crack when exposed to rapid changes in temperature.

Aragonite is one of two common calcium carbonate (CaCO3) minerals: the other is calcite, of which aragonite forms as a pseudomorph. Its crystal lattice differs from calcite, resulting in a different crystal shape. It displays a translucent to white color when pure, and when impure can vary between yellow, green, pink, blue and brown. It typically forms in low-temperature hydrothermal veins, in hot springs, and as precipitates from chemicals in sedimentary rock. It can also form under biological processes: aragonite forms naturally in most mollusk shells, and as the calcareous endoskeleton most corals.