ee of its axes are equal to one another?and all have 120?angles arranged in one plane. The other axis has a right angle and is not equal with the other three. Approximately eight percent of all minerals crystallize in the hexagonal system. Pyrrhotite, contains sulfur and is found with nickel. Pyrrhotite crystals occur in thin plates and have a brassy bronze color. Covellite, has colors of deep blue?black?and purple. Covellite also occurs as thin plates in crystal form. Molybdenite, a soft mineral in the colors of metallic blur- gray. Apatite, a transparent and translucent mineral that is found in quartz and feldspar. These crystals all crystallize in the hexagonal system.
             Like the isometric system, the orthorhom
             ...