Carbon ($C$), makes up for the majority of our planet and everything that lives on it. Coal, gems (any gem), plants, and most sedimentary rocks also contain great deals of carbon.
Fun fact: Coal is almost purely carbon; due to it being made entirely of decayed plants and animals.
I'd prefer a fraction or percentage answer (ex. about 1/3 or 34%) Rounded, if you would.
About how much of planet Earth is carbon based?
Proportion of $C$ to really anything else.