Amosite and crocidolite are both amphiboles, which you will recall are chain silicates Their crystal architecture is based on silicate tetrahedra bonded together in linear sets. The ions within each chain are bonded strongly but the bonds holding each chain to its neighbors are much weaker. Thus the structure of amphiboles would tend to favor the formation of fibers.

But what about chrysotile? It is a sheet silicate. Generally such a structure would favor the formation of flakes or sheets rather than fibers.

To investigate the reason behind this unusual physical property of the serpentine mineral, chrysotile, use the interactive table below.