Graphite is a natural mineral, one of allotropic modifications of carbon. It has layered structure. The layers of the crystal lattice can arrange different relative to each other, forming a number of types: symmetrical, hexagonal, dihexagonal, dipyramidal, triangle, ditriangle, and etc . The layers are weak, almost flat, consisting of hexagonal layers of carbon atoms. Crystals are lamellar and flaky. Crystals form foiled and rounded radial-radiant aggregates. Sometimes, it has concentric-zonal structure.  Coarse-crystalline secretions often have a triangular hatching.