In the future can we turn carbon emissions into diamonds?

It’s almost certainly cheaper to convert the already concentrated carbon (coal) to diamonds-the current practice. Besides, if such a technology were miraculously developed the price of diamonds would plummet. As it is already the price of diamonds is artificially sustained through the shrewd manipulation of outfits like deBeers.

It takes a tremendous amount of energy to make artificial diamonds.
If the point is carbon capture then you’d have to make sure you have power from non-fossil-fuel source for it to make any sense at all. If you do have such a non-fossil-fuel power source you might as well just use that instead of whatever is making the carbon emissions.

Diamonds made from carbon dioxide might have some value, though as @stanleybmanly wrote, the supply of low cost diamonds would make them as desirable as glass for jewelry. However, it would be valuable for industrial use. And as @dabbler said, the cost to convert CO2 to diamonds in terms of environmental and monetary costs would be prohibitive. Then there is the problem of how much CO2 would be necessary for a given weight of a diamond or a quantity of diamond dust. My guess is that the amount of carbon dioxide converted to pure carbon (which would later be compressed into diamonds) would be negligible.

My fantasy is to convert carbon dioxide and methane (CO2+CH4) into two parts carbon and two parts water (H20). Because carbon has double-valance bonds with oxygen, considerable energy is required to break them (possibly in the form of electromagnetism/photon with a wavelength proportionate to the distance between the carbon and oxygen atoms). However, as hydrogen bonds with oxygen energy is released that may be used to attack the carbon bonds.

You would first have to change the carbon dioxide (CO2) gas in the atmosphere back into the basic carbon© element before you could make diamonds. It would take one heck of a lot of effort and energy to do this, I’m thinking, with little result cost-effective wise.

@kritiper, the value of pure carbon likely exceeds that of diamonds even at today’s prices. Plus, imagine what burning pure carbon will do to eliminate contaminates that coal contains. And capture the CO2 and add some methane and the cycle continues. Fantasy, as I said.