Upon completion of this module, you should be able to understand the difference between amorphous and crystalline solids, understand the differences between various types of crystalline solids, and know important characteristics of the various types of crystalline solids. There are two types of solids: amorphous and crystalline. Amorphous solids have molecules or atoms that are not organized in any definite pattern. Glass, rubber, and plastic are examples of solids that are amorphous.