What is the difference between amorphous and crystalline substances?

Amorphous and crystalline are two states that describe typical solids in chemistry. Using X-ray diffraction experiments, the structure of solids can be classified as crystalline or amorphous (non-crystalline).

A crystalline solid is one in which the constituent particles are ordered in a three-dimensional pattern called a crystal lattice with uniform intermolecular forces, and the particles intersect at angles characteristic of the crystal.

An amorphous substance is a shapeless, disordered and irregular arrangement of the constituent particles of a solid. Their intermolecular forces do not coincide, as well as the distances between particles. When cleaved, amorphous solids give fragments or curved surfaces due to irregular geometric shapes.