Anticrystal

An anticrystal is a theoretical solid that is completely disordered, making it the opposite of a crystal. The mechanical properties of even a slightly disordered solid can have more in common with an anticrystal than with a crystal.

All naturally-occurring crystals contain disordered areas (defects). Scientific descriptions typically assume a perfect crystal, extrapolating from that point based on defect prevalence. However, given sufficient defects, extrapolation from perfect crystals fails. Amorphous materials may display regions with atoms in repeating patterns, but without crystalline order. This means that their properties cannot be inferred from those of a perfect crystal.