interfacial angle

In crystallography, the interfacial angle refers to the constant angle between corresponding faces of a crystal. This principle, known as Steno's law or the law of constancy of interfacial angles, states that these angles are characteristic of the specific chemical substance or mineral, regardless of the crystal's size or origin. This discovery was foundational in crystallography, with later work suggesting that crystals are composed of minute building blocks that account for these consistent angles. Instruments like the goniometer are used to measure these interfacial angles. Crystallography itself is the science dedicated to understanding the arrangement of atoms within crystalline solids and the geometric structure of crystal lattices.12345