
Pedion
A single face comprising of a form (1)

Pinacoid
 An open form made up of two paralle faces (2)
 2fold axis or bar 1
 monotriclinc

Dome
An open form consisting of two nonparallel faces symmetrical with respect to a mirror plan (m) (3)

Sphenoid
Two nonparallel faces symmetrical with respect to a 2fold axis (4)

Prism
An open form composed of 3,4,5,6,8, or 12 faces, all of which a are parallel tow the same axis. Except for certain prisms in the monoclinic system, the axis is one of the crystallographic axes (511)

Pyramid
An open form composed of 3,4,6,8, or 12 nonparallel faces that meet at a point (1218)

Scalenohedron
A closed form with 8 or 12 faces grouped in symmetrical pairs. In the tetragonal scalenohedron, pairs of upper faces are related by an axis of fourfold rotoinversion to pairs of lower faces. The 12 faces of the hexagonal scalenohedron display three pairs of upper faces and three pairs of lower faces in alternating positions. The pairs are related by a center of symmetry, wichis is part of a 3fold rotoinversion, bar 3. In an ideally develped scalenohedron, each face is a scalenen triangle

Rhombohedron
 A closed form composed of six faces of which three faces at the top alternate with threee at the bottom, the two sets of faces being offset by 60 degrees.
 Are only found in point groups of bar3 2/m, 3 2, and bar 3.

Disphenoid
A closed form consisting of two upper faces that alternate with two lower faces, offset by 90 degrees

