Wurtzite structure

Wurtzite is the less common mineral form of ZnS. Its structure is below:

It is a hcp array of anions with cations inside half the tetrahedral holes. Here is what a standard hcp array looks like, it might be easier to learn this first:

 

This structure is also adopted by a mineral form of ZnO, Zincite.

Zincite is transparent. It is coloured red here from iron and magnesium impurities.

Ordinary ZnO is a white powder used a treat a variety of skin conditions. Like TiO₂, it absorbs UV and can be used in sunscreen. Many breakfast cereals contain it as a source of zinc.

This structure is also adopted by silver iodide (the stuff they use to seed clouds) up to 147°C in the mineral Iodargyrite.

The Iodargyrite is yellow