Glass-ceramics combine the properties of glasses with the benefits of conventional sintered ceramics.
Most commonly they are manufactured in a process in which a pre-manufactured glass is subjected to a specific heat treatment. This treatment results in a controlled nucleation and crystallisation of the glass. The glass partially crystallises, and the glass-ceramic develops a structure comprising an amorphous (glassy) phase and at least one embedded crystalline phase .
Glass-ceramics can range from highly crystalline to containing a more substantial glassy phase. As they contain crystalline phases and, therefore, also grain boundaries, glass-ceramics can range from transparent to opaque [1,2].
Depending on the microstructure and the chemical composition of glass-ceramics, their properties can be tuned to meet demanding requirements. In general, glass-ceramics exhibit almost zero thermal expansion and high toughness. In addition, they are resistant to thermal shock and have a high impact resistance .
Glass-ceramics can be subdivided into two categories: oxide and non-oxide. Oxide glass-ceramics include silicate (SiO2), borate (B2O3), phosphate (P2O5) and germinate (GeO2) type materials. Non-oxide glass-ceramics include chalcogenide, halide and metallic type. 
With their thermal and mechanical characteristics, glass-ceramics have a range of applications, including:
If you would like to know more about glass ceramics, read this article: "Glass-ceramic for extreme conditions".
 W. Höland, G. H. Beall, Glass Ceramic Technology. John Wiley & Sons, 2012.
 B. Karmakar, Functional Glasses and Glass-Ceramics: Processing, Properties and Applications. Butterworth-Heinemann, 2017.
Glass-ceramic is a material that combines two types of materials to form a product that is in a class of its own between glasses and polycrystalline ceramics.