"Orthorhombic. Crystals commonly tabular parallel to basal plane, showing also short prisms and low brachydomes." — Ford, 1912

Marcasite

"Orthorhombic. Crystals commonly tabular parallel to basal plane, showing also short prisms and low…

"Orthorhombic. Crystals commonly tabular parallel to basal plane, showing also short prisms and low brachydomes. The brachydomes usually striated parallel to the brachy-axis. Often twinned, given coxcomb and spear-shaped groups." — Ford, 1912

Marcasite

"Orthorhombic. Crystals commonly tabular parallel to basal plane, showing also short prisms and low…

This form shows the fundamental prism (p) on a crystal of topaz, in combination with another prism, (p'); the basal pinacoid, (c); the brachydome, (g); and the four pyramids, (o), (o'), (o''), and (x).

Orthorhombic Crystal of Topaz

This form shows the fundamental prism (p) on a crystal of topaz, in combination with another prism,…