noun
crystal axis
Technical term in crystallography and mineralogy; refers to a reference line used to describe the symmetry and orientation of a crystal lattice.
結晶軸の方向によって、鉱物の光学的性質が異なる。
The optical properties of a mineral differ depending on the direction of the crystal axis.
Compound of 結晶 (kesshō, 'crystal') and 軸 (jiku, 'axis').