Any substances that consists of closely packed particles (atoms, molecules or ions) is called solids. The solids having characteristic geometrical forms are known as the crystalline solids. These solids posses a regular and repeated arrangement of particles.
Solids are of two types: Crystalline and amorphous. The main feature of the crystalline solids is their long range order and solids posses short range of order is known as amorphous solids. Amorphous solids are known as glassy solids. (Crystalline vs Amorphous Solids)
Example of Crystalline solids: Rock salt, Calcite and quartz
Example of Amorphous solids: Glass and sugar candy