Graphite crystals. Coloured scanning electron micrograph (SEM) of a graphite polyhedral crystal (GPC) growing in a pore of glassy carbon (yellow). This crystal is a twisted rod (blue) displaying heptagonal (seven-sided) symmetry. These crystals are an unusual form of carbon found in the pores of industrial glassy carbon, grown under hydrothermal conditions of high temperature and pressure. Extremely thin, needle-like carbon nanotubes develop into the highly ordered GPCs found in this environment. Larger GPCs could find applications in nanotechnology for their high electrical conductivity, strength and chemical stability. Magnification: x60,500 at 6x7cm size.