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.Â
These solids posses a regular and repeated arrangement of particles.Â
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