A quick search has enabled me to calculate some rough carbon prices based on small quantities of the substances.
Carbon black pigment $80,000 tonne
Graphite powder $34,000 tonne
Diamonds 2 carat $150,000,000 tonne
So there be money in carbon.
I think when Penny Wong talks about carbon pollution she actually means CO2pollution,CO2 is not a pollutant but a trace gas in the atmosphere necessary for most life on the planet.
I have found a price on CO2 food grade, 6.8 kg $45 which works out at $6617.64 a tonne. Sorry to be so flippant but the whole thing is quite silly, putting a price on a naturally occuring subbstance which is basically free if you if you can extract it. It's like putting a price on sea water, now there's a challenge.