Crystals of the notched or grooved type are known from some minerals which crystallise in the cubic system. From diamond grooved octahedrons are known, whose grooves remind us of octahedral faces, or the faces of triakis octahedra or hexakis ostahedra. From haüynite too grooved octahedrons are pictured, whose grooves are bordered by octahedral faces. Grooved analcite is known in icositetrahedrons, the grooves are bordered by faces of the same icositetrahedron.