There are some fascinating quantum properties of defects (or vacancies) in the structure of diamonds --- called NV centers.
This week we have Florian Dolde and Ya Wang visiting us so I'm now remotivated to finish off this
NV centers introduction.
The fun thing found is using the graphical view of the roots of the cubic, related to the magnitude of a static electromagnetic field, and the angle of the symmetry axis relative to this field. In other words, it gives a neat picture of some physical quantities that are important to NV centers!