Crystalline solids are anisotropic their mechanical, electrical and optical properties depends upon the direction along which these are measured ( in the lattice).eg.Diamond, NaCl.
Amorphous solids are isotropic ( iso - equal, tropos - turn ) as these above properties do not depend on the direction of measurement. eg. glass, rubber.
As in the attachment ... Anisotropic crystal when made cuts in diffrent direction they show different molecule arrangment.