Changes

Four [[axes of symmetry]]: three, of equal length, lie in a plane at 120°; the fourth axis is longer or shorter and is at [[right angles]] to the others.

Four [[Axis|axes]] of [[symmetry]]: three, of equal length, lie in a plane at 120°; the fourth axis is longer or shorter and is at [[right angle]]s to the others.

[[Crystals]] are generally [[prismatic]] or [[columnar]], with rounded [[triangular]] or [[hexagonal]] cross section; characteristic forms are three- or six-sided [[prisms]], [[pyramids]], and [[rhombohedrons]]. The very similar ''[[trigonal system]]'' is often included within the hexagonal system. Chesterman, pp. 33-34

[[Crystals]] are generally [[prismatic]] or [[columnar]], with a rounded [[triangular]] or [[hexagonal]] cross section; characteristic forms are three- or six-sided [[prism]]s, [[pyramid]]s, and [[rhombohedron]]s. The very similar ''[[trigonal system]]'' is often included within the hexagonal system. Chesterman, pp. 33-34

=Sources=

=Sources=

*Chesterman, Charles W. ''The Audubon Society Field Guide to North American Rocks and Minerals'', Alfred A. Knopf: New York (1987)

*Chesterman, Charles W. ''The Audubon Society Field Guide to North American Rocks and Minerals'', Alfred A. Knopf: New York (1987)

[[category:geometry]]

[[category:geometry]]