Re: how to identify Graphite Ore?

Whenever you want to identify a particular mineral, there are many different 
books that you can purchase which have good descriptions of minerals and how 
to identify them.  My favorite guide is the "National Audubon Society Field 
Guide to North American Rocks and Minerals", which you should be able to 
find at a local bookstore.  The information that I can tell you about how to 
identify graphite comes from that guidebook, as well as an introductory 
mineralogy textbook (both references are listed below).

Graphite is formed when sediment that is rich in carbon (like organic 
material) is altered either by heating the sediment up or applying a 
pressure to it for long periods of time (this might happen if you bury the 
sediments).  Because of this, graphite is often found among other 
metamorphosed minerals and rocks, such as quartz, muscovite and limestone.  
In general, graphite is dark grey or black, looks slightly shiny or metallic 
and should feel greasy on your hands.  One of the most distinguishing 
characteristics of graphite is that it is extremely soft; if you find 
graphite, you will be able to scratch it and make a mark with your 
fingernail.  Also, if you take a piece of the graphite and try to draw on a 
white surface, it will easily make a black mark.  Finally, if you get a good 
size piece of graphite, it may look foliated or layered to you.  This is 
because the crystal structure of graphite is simply layer upon layer of 
sheets of carbon, like a stack of note cards.  So, to identify graphite, 
look for a very dark grey to black rock that you can easily scratch with 
your fingernail and will mark on other surfaces (much like a pencil lead).  
You may need a magnifying glass to notice the layers within the graphite.

Here is a web page that has a photo of a large chunk of graphite on it.  
You can see how the graphite looks shiny and has layers in it:
  http://www.minerals.net/mineral/elements/graphite/graphit1.htm

This image shows how graphite can be a small part of a larger rock (in this 
case quartz):
 http://
www.geology.neab.net/pictures/rock130.jpg

References:

Chesterman, Charles W.  (1997) National Audubon Society Field Guide to North 
American Rocks and Minerals. Chanticleer Press, New York.

Klein, Cornelis & Hurlbut, Cornelius (1993)  Manual of Mineralogy.  John 
Wiley & Sons, New York.