Differences between Crystalline and amorphous Solids

The crystalline and amorphous solids differ from one another in the following respects.

1.   Characteristics Geometry: - Crystalline solids have definite and regular geometry and this extends throughout the crystal. Thus, they have long range order. On the other hand, the amorphous solids do not have any regular arrangement of constituent particles. Some amorphous solids have only short range order.
2.   Melting Points: - the crystalline substances have sharp melting points, i.e., they abruptly change into liquid states. On the other hand, the amorphous solids do not have sharp melting points. For example, when glass is heated gradually, it softens and starts to flow without undergoing a definite and abrupt change into liquid state.
3.   Isotropy and anisotropy: - the substances which have physical properties such as electrical conductivity, refractive index, thermal expansion etc. same in all directions are called isotropic substances. On the other hand, the substances which have their physical properties different in different directions are called anisotropic substances. They crystalline solids are anisotropic. Therefore the physical properties of crystalline solids are different in different directions. The anisotropic properties of crystalline solids are isotropic and therefore, their physical properties are same in all directions.
4.   Cleavage: - when the crystalline solids are cut with a sharp edged tool, they are cleaved along preferred directions. On the other hand, the amorphous solids undergo irregular breakage when cut with a knife.