What does it look like?
What is it?
Augite is a very dark green to black colourer mineral. It is made up of silicate chains with principally magnesium, iron, calcium and aluminium atoms sitting between them. There’s quite a variation in which of these elements are found in the structure, but the chains mark the structures as belonging to the pyroxene family of minerals – like Jadeite. One of the striking features of this mineral is its, ahem, cleavage. Many minerals will split open along particular directions, this is usually from a weakness in their crystal structures. Augite has two prominent cleavages, which meet at about 90 degrees.
Where did the structure come from?
The crystal structure of wurtzite is #1200006 in the open crystallography database.