Assorted hardened non-metallic materials, made by firing them at high temperatures. Common compounds for their production include clays, metal oxides, nitrides, and carbides.
Ceramics are typically very strong under compression, and weak under shearing or tension. They are generally brittle and will shatter or snap rather than bend.
They are typically vitrified or semi vitrified (i.e. turned into a glass, at least partially) when composed of clays.