Characteristics of Hexagonal Crystals 12 crystal classes divided into 2 groups hexagonal division with a 6-fold symmetry axis rhombohedral division have a 3-fold symmetry axis Four crystallographic axes of equal length with angels of 120 degrees. The fourth axis is vertical. Dihexagonal dipyramid Prism Scalenohedron Rhombohedron Common Minerals of the Hexagonal System Hexagonal Division Quartz Kalsilite Benitoite Wurtzite Greenockite Zincite Apatite Nepheline Rhombohedral Division Calcite Corundum Hematite Brucite Soda niter Arsenic Millerite Antimony Bismuth Cinnabar Berlinite Tourmaline Pyraragyrite Prouslite Alunite Dolomite Ilmenite Willemite Phenacite

Crystal Systems/All About Crystals