How can you tell if an item is made of porcelin or if it bisque?

Answer 1

Porcelain is made with ground animal bones and that is what gives it a bell like ring if you tap the edge. It is fired at a very high temperature and therefore is relatively strong. If you hold it up to a strong light, you can see the glow of light through porcelain.
Bisque is fired at a lower temperature and has a 'clink' sound if you tap the edge. (But be careful, since bisque is much softer, it chips easily.) When you hold it up to the light, it is completely opaque.
The sound and the light test are the quickest ways to tell the difference.

Answer 2

The only thing I know is that bisque has a mat finish and porcelain has a shiny smooth finish.