A mineral is defined by its chemical composition and by its crystal structure. The latter is a three-dimensional srrangement of atoms in a solid crystal. In general, each mineral of a defined composition has one matching structure.

About 4000 different minerals exist on earth. Of these less than a hundred minerals are known to be dimorph, which means that they have the same composition but two different structures. Less than 20 minerals are known to be trimorph which means that they have three different structures.

The reason for a different structure is a significant change of enviromental conditions, as temperature and pressure, during formation of the mineral. These differences make it very rare that different structures of one mineral exist at one locality. Furthermore, it is likely impossible that crystals of the same minerals, but of differnt structures, exist on one specimen. Such an occurence would indicate that the enviroment has changed dramatically within an unusual short time during crystallisation.

Therefore, it is like finding a needle in a hay ball if you discover a mineral specimen which exhbits several crystal structures of the same mineral. It might look like a miracle, but it is only a matter of statistic plausibility.

Within 30 years of collecting, we were lucky to find 2 specimens which show crystals of both structures of a dimorph mineral and only one specimen which has crystals of all three structures of a mineral.