Interrelationship «structure-hardness-fusibility» for oxide crystals

The indistinct interrelationship between the mel-ting temperature (T
_m
), Mohs hardness (H
_s
), thermal con-ductivity (k), and structure of many oxide synthetic crys-tals, and minerals has been established more detail. It is shown that the external boundary of the full set {H
_s
- T
_m
} is res-tricted with 7-side polygon. These data has been useful at search of the most hardness and heat-conducting materials for optoelectronic devices.