Orthorhombic System

The orthorhombic system is defined by three mutually perpendicular axes, all of which have unequal lengths.

Geometrically, it takes the shape of a rectangular prism. It is a unique and highly versatile system in crystallography, as it is the only one that accommodates all four Bravais lattice types: primitive ($P$), base-centered ($C$), body-centered ($I$), and face-centered ($F$).

From a symmetry perspective, it is characterized by three mutually perpendicular two-fold rotation axes or mirror planes. Because the edge lengths are all different ($a$, $b$, and $c$), physical properties like electrical conductivity or refractive index often vary depending on the direction of measurement, a phenomenon known as anisotropy.

Lattice parameters: $a \neq b \neq c$, and angles $\alpha = \beta = \gamma = 90^\circ$.

Examples: Alpha-Sulfur (rhombic), Olivine, Topaz, and Aragonite.