Has Vanna White ever tripped? Who is the lady on Wheel of Fortune who seems to be pretending to be Vanna? Does Vanna White ever wear the same dress more than once on the Wheel of Fortune? How much money could a game make if it made it to network TV on prime time, say 8pm ET after Jeopardy! and Wheel of Fortune?
Among minerals of economic importance, carbon minerals hold the unique position of being at the same time of the most common and the most rare occurrence.
Coal is not a mineral, because it can not be expressed as a chemical formula, and therefore, does not have a definate crystaline structure. Coal is predominately carbon. The specimen in the photo is Bituminous Coal, with a carbon content of about 90%, and a BTU rating of over 13,000 BTU/pound.