en.wikipedia.org/wiki/Hexagonal_crystal_systemThe hexagonal crystal system consists of the 7 point groups that have a single six-fold rotation axis. These 7 point groups have 27 space groups (168 to 194), all of which are assigned to the hexagonal lattice system. Graphite is an example of a crystal that crystallizes in the hexagonal crystal system.
www.britannica.com/science/hexagonal-systemHexagonal system, one of the principal categories of structures to which a given crystalline solid can be assigned. Components of crystals in this system are located by reference to four axes—three of equal length set at 120 degrees to one another and a fourth axis perpendicular to the plane of the other three.
uwaterloo.ca/earth-sciences-museum/resources/.../hexagonal-crystal-systemHexagonal crystal system. The hexagonal system has four crystallographic axes consisting of three equal horizontal, or equilateral axes at 120 degrees to each other, as well as one vertical axis which is perpendicular to the other three. This vertical axis can be longer or shorter than the horizontal axes.
www.mindat.org/article.php/2850/Crystallography%3A+The+Hexagonal+SystemPyramids in the hexagonal crystal system may have 3, 6 or 12 faces, all converging on and meeting at a single end of the c axis. Dipyramids have 6, 12, or 24 faces, half meeting on the positive end and half on the negative end of the c axis. Pyramids are analogous to half a dipyramid and are open forms (the form requires other forms in ...
metafysica.nl/hexagonal_1.htmlWith all this we have found yet another basic face compatible with the Hexagonal Crystal System, namely the face 2a : 2a : -a : ~c. The last Form to be discussed is the basic pinacoid. It consists of two faces, parallel to each other and to the equatorial plane of the system of crystallographic axes. This Form is, like the prisms, an open Form ...
www.geologyin.com/2014/11/crystal-structure-and-crystal-system.htmlThe hexagonal crystal system is further broken down into hexagonal and rhombohedral divisions. Every crystal class which belongs to a certain crystal system will share a characteristic symmetry element with the other members of its system. For example, all crystals of the isometric system possess four 3-fold axes of symmetry which proceed ...
www.yourgemologist.com/crystalsystems.htmlThis is where the debate lies regarding whether or not the trigonal system is a system into itself or simply a sub-category of the hexagonal crystal system. In the United States it is taught that the trigonal system is a sub-system of the hexagonal.
www.wikigempedia.com/gemstone-crystal-system-chart.htmlBased on the crystal axes and the angles at which the axes intersect, crystals are divided into seven systems including, Cubic, Tetragonal, hexagonal, trigonal, Orthorhombic, Monoclinic, and Triclinic systems.
www.gemsociety.org/article/gems-ordered-crystal-systemThe following table contains a selection of minerals gemologists may encounter as jewelry stones or gem specimens. The gems are sorted by their crystal system: cubic (isometric), tetragonal, hexagonal, trigonal, orthorhombic, monoclinic, and triclinic.
en.wikipedia.org/wiki/Crystal_systemA lattice system is a class of lattices with the same set of lattice point groups, which are subgroups of the arithmetic crystal classes.The 14 Bravais lattices are grouped into seven lattice systems: triclinic, monoclinic, orthorhombic, tetragonal, rhombohedral, hexagonal, and cubic.. In a crystal system, a set of point groups and their corresponding space groups are assigned to a lattice system.