Crystalline materials :
they have long range order .
anisotropic in nature .(get different values for some physical quantities like refractive index , conductivity when measure in different directions )
particles ( atoms , molecules , ions ) are regularly arranged .
when a crystalline solid is cut with a sharp edged tool , we get a smooth surface.
Amorphous solid :
they have short range order.
isotropic in nature.
particles are irregularly arranged .
when an amorphous solid is cut with a sharp edged tool , we get irregularly arranged rough surface .
they are also called pseudo solid and super cooled liquid .