Solids
Solids have definite shape and volume. Solids are composed of particles that vibrate close to one another but lack the energy to break free. This allows them to have a definite shape. There are two types of solids. Crystalline solids and Non-crystalline solids.
Crystalline Solids
Most solids consist of particles that form a definite geometric shape called a crystal. The difference between one solid and another is the type and shape of the crystal forms.
Non-crystalline Solids
These types of solids are called amorphous solids because they do not have crystals that form when they turn into a solid. Examples of this class of solid would be some plastics, wax and glass. Some scientists actually feel that if a solid has no crystalline formation that it could possibly be classified as a very thick liquid. This again is because of the lack of crystalline lattice work to hold it together.