Ceramic is mainly covalent and is made of oxides of elements. (more info: Ceramic chemistry - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Ceramic_chemistry))

Whereas Stainless steel is an alloy of metal.

Long ago, ceramics had a limited use, but now, new ceramics are being created which have amazing properties, some which match or even surpass the properties of metals and their alloys.