I picked up a couple of fancy little rocks at a Mineral store in Seattle. This one pictured below, Ulexite, is a.k.a. TV Rock. You can get an idea from the picture why they call it that: it transmits images. The rock is made up of bundled fibers which act as fiber optics, reflecting light along the fibers from whatever is adjacent the other side. Pretty effing cool if you aks me.
Another thing about ulexite, also cool, it will dissolve in water. Because it’s made mostly of salt!