 crystals melt when the average amplitude of thermal vibrations of atoms is relatively high compared with interatomic distances, e.g.2">1/2 > "δLRs", where "δu" is the atomic displacement, the Lindemann parameter "δL" ≈ 0.20...0.25 and "Rs" is one-half of the inter-atomic distance.The Lindemann melting criterion is supported by experimental data both for crystalline materials and for glass-liquid transitions in amorphous materials.