What do graphite and charcoal have in common?

Both graphite and diamond are forms of carbon. As such, they are said to be alotropes of carbon. Both occur naturally. Both are mined for industrial purposes, though larger diamonds are sought and used for other things. Both are produced in the earth in geothermal processes. Both can be made artificially. Both are normally solids and highly stable. And they are both difficult to burn, even in an oxygen environment.