im going to be making a type of mosaic collage with a load of old tiles, is there any way to visually tell the differance between ceramic and porcelain tiles?

Open Question: Differance Between Ceramic and Porcelain Tiles? for the full Yahoo Question / Answer.

Ceramics have a 'biscuit' back that is a different colour (usually brown ish) to the glazed surface. Generally thinner as well as the are mostly used on walls.
Porcelain are a uniform colour throughout & are denser & thicker as used on floors, the tiles have a nice 'ping' if you flick them and will say 'porcelain' on the back

Well said Davie, Main diference - ceramic is a biscuit often with a glazed finish and porcelain is the same colour all the way through (through bodied)

Good answers guys but they have not appeared on the yahoo site..guess you have to click the yahoo link and then type them in...