Silicon Specimen Pieces

These are lab made pieces of purified silicon, 99.999% pure polycrystalline material made in Germany.  Some pieces show the surface of the ingot, where cooling formed different crystal structures.  Others have just fractured and show the natural gray/black of silicon.  They are neat little artifacts of science.

Silicon is famously used in all sort of computer chips and other technical applications, and large silicon monocrystals have driven the development of the Czochralski growth method.  While the Moh's hardness is middling at 6.5, this material is quite brittle so is a bit difficult to facet.  Still, it could be a fun challenge.