I'm looking for information to help me identify industrial waste and 
byproducts.
In the past, I've had either glassy/bubbly or more metallic material 
that I have simply classified as slag.  But I now have a crew doing work 
in a steel town in western Pennsylvania (Braddock) and want to know 
whether there are distinctions I should be making within slag.  Also 
what does coke look like (made from coal for steel plant fuel)?  What 
about other coal waste ("clinkers")?  or other products that I would be 
likely to encounter in that setting.  I've seen everything from black to 
ashy beige materials, to a very blue-ish gray; some dense, some very 
light and full of air bubbles like pumice.  I can see that they are 
different materials, but don't know where to look, to learn how to 
better classify them.  So any descriptions, pictures, or directions to 
an informative website would be greatly appreciated.
Melissa Diamanti
Archaeological & Historical Consultants, Inc.