ClipArt ETC
This figure, representing Acanthite, an orthrohombic crystal, shows a combination of the following forms: (a), (b), (c), (l), (m), (o), (e), (d), (k), (p), (s), (r), and (n).

Acanthite

This figure, representing Acanthite, an orthrohombic crystal, shows a combination of the following forms:…

This figure represents a crystal of iron pyrite showing representatives of all the forms of the isometric system except the rhombic dodecahedron: ∞O∞ {100} (P); O, {111} (d); [∞O2/2], π{102} (e); [4O2/2], π{214} (s); 2O2, {211} (o); and 3O, {133} (t). It is shortened in the direction of one of the principal axes, which, together with the fact that only two of the three faces belonging to the forms s, o, and t are developed in each octant, gives to it a decidedly orthorhombic habit.

Crystal of Iron Pyrite Showing Representatives of All the Forms of the Isometric System

This figure represents a crystal of iron pyrite showing representatives of all the forms of the isometric…

Cubes of Iron Pyrites frequently show a striation of their planes in one direction, which is perpendicular to the striation on all contiguous faces, owing to oscillatory combination with the pentagonal dodecahedron. This would not be possible in a holohedral cube.

Cube of Iron Pyrite

Cubes of Iron Pyrites frequently show a striation of their planes in one direction, which is perpendicular…

It has been observed that the pentagonal dodecahedron, [∞o2/2], π {201}, on pyrite may have but six of its twelve planes developed in such a manner a to produce an apparent rhombohedron.

Pyrite

It has been observed that the pentagonal dodecahedron, [∞o2/2], π {201}, on pyrite may have but six…

An example of sphenoidal crystallization is Iron-Copper-Sulfide (FeS_2_Cu), also known as chalcopyrite.

Sphenoidal Crystallization

An example of sphenoidal crystallization is Iron-Copper-Sulfide (FeS_2_Cu), also known as chalcopyrite.