Amorphous and crystalline are types of solid. Crystalline solids are those solids in which ions and atoms are arranged in a regular pattern but amorphous solids do not have any regular pattern in their structure. So, the classification of solids can be done on the basis of amorphous and crystalline solids. By the physical properties like melting point and boiling point, a solid can be identified.
Crystalline solids are divided into four categories
Ionic solids- The solids which contain positive and negative ions which are attracted by the electrostatic force of attraction. They have high melting points
Molecular solids- These solids are made up of atoms which are bonded by London forces. They have a low melting point and are poor conductors of electricity.
Covalent network solids- The network of these solids is linked by covalent bonds. They have a high melting point and are poor conductors of electricity
Metallic solids- The atom in the solids have metallic bonding. They have a high melting point and are good conductors of electricity.
So, by the physical properties and type of bonding solids can be identified.