factor 30, - gosh, there are two of you!
Carbon occurs naturally in three forms:
Graphite is the purest form of carbon found in nature. Clear diamond is also pure carbon.
Coal is mainly carbon but not pure.
All other forms of carbon (soot, lampblack, coke, charcoal,etc.) are not natural (and usually not pure) but are commonly the result of heat of some sort.
I am puzzled by that fact that because the different forms of carbon are given different names you deny that they are carbon. Very odd. Do you deny that ozone consists solely of the element oxygen?
(By the way, you can burn diamond. And what you get is pure carbon dioxide, nothing else.)
I know that carbon is not the answer to the original question. I was merely taking up EDDIE1's extraordinary claim that graphite isn't an element. Cheers.