Thanks John!
would like to find a piece of mars or the moon with a dead martian worm in it - i would be RICH! HAHAHHAHHAA
sorry Geoff about the short answer - just googled - many great sites on the subject - they would probably hve a different look to surrounding rocks at a guess - they can be melted looking on the outside - and look different inside ect.
http://www.solarviews.com/eng/meteor.htm
http://www.meteorites.com/
great trivia fact about meteorites - you would think normally they would be hot to the touch straight after landing - but in fact they are often very cold after being cooled by the trip through the lower atmosphere