Ceramics are inorganic, nonmetallic materials whose structures are commonly dominated by ionic bonding, covalent bonding, or mixtures of both.

Strong primary bonds often give ceramics high elastic stiffness, high melting or decomposition temperatures, good wear resistance and chemical stability. Their bonding and crystal structures also make crystallographic slip and extensive plastic flow difficult in many ceramics at room temperature, so fracture can occur after little permanent deformation.

Ionic ceramics must satisfy local and global charge neutrality. Relative ion sizes and charges constrain which coordination arrangements and crystal structures are stable. Covalent ceramics tend to favor directional bond geometries.

Many ceramics are electrical insulators because electrons are localized in filled bonding states, although ceramics also include semiconductors, ionic conductors and superconductors; 'ceramic' is a structural/material class, not an electrical-property definition.

Ceramic performance is especially sensitive to pores and cracks because limited plasticity provides little crack-tip blunting. Processing quality therefore has a direct effect on measured strength.

The broad pattern is consequently strong bonding + constrained plasticity + flaw sensitivity. Specific ceramic families modify this pattern through phase transformations, microstructural toughening, porosity and specialized electronic or ionic transport.