The difference between crystalline and amorphous

"The difference between crystal and amorphous: different self normity, different arrangement, different anisotropy and different melting point.
Crystals are anisotropic, while amorphous crystals are mostly isotropic. The crystal has a fixed melting point, while the amorphous has no fixed melting point, and its temperature increases with heating during the melting process. "
The particles (atoms, ions, molecules, atomic clusters) in the internal structure of the crystal are regularly and repeatedly arranged in the three-dimensional space, forming a lattice of a certain form, which is a geometric polyhedron of a certain shape in appearance. The plane that forms a certain geometric polyhedron is called crystal plane. Due to different growth conditions, the crystal may be slightly skewed in shape, but the included angle (crystal plane angle) between crystal planes of the same kind is certain, which is called the principle of crystal plane angle invariance.
It is called element system, and the corresponding symmetrical action group is called crystal system point group. According to the nature of the force between internal particles, crystals can be divided into four typical crystals, such as ionic crystals, atomic crystals, molecular crystals, and metal crystals, such as salt, diamonds, dry ice, and various metals. The same crystal also has the difference between single crystal and polycrystalline (or powder crystal).